Terminal, method of manufacturing terminal, and termination connection structure of electric wire

ABSTRACT

A terminal includes a tubular crimp portion that crimp connects with an electric wire. The tubular crimp portion is composed of a metal member. The tubular crimp portion includes a non-weld portion and a weld portion, the weld portion being formed by welding. A metal base material constituting the metal member of the non-weld portion includes a normal portion and an annealed portion.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation application of U.S. application Ser. No.14/290,503 filed on May 29, 2014, the full contents of which is herebyincorporated by reference in its entirety. U.S. application Ser. No.14/290,503 is a continuation application of International PatentApplication No. PCT/JP2013/070523 filed Jul. 29, 2013, which claims thebenefit of Japanese Patent Application Nos. 2012-167779, 2013-034022 and2013-034023, filed Jul. 27, 2012, Feb. 23, 2013 and Feb. 23, 2013,respectively, the full contents of all of which are hereby incorporatedby reference in their entirety.

BACKGROUND

Technical Field

The present disclosure relates to a terminal with a reduced possibilityof cracking during crimping and springback after crimping as well as animproved anticorrosion property, a method of manufacturing thereof, anda termination connection structure of an electric wire.

Background Art

In the related art, a connection between an electric wire and a terminalin an automotive wire harness or the like is generally a crimpconnection in which an electric wire is crimped with a terminal which isreferred to an open barrel type. However, with an open barrel typeterminal, when moisture or the like comes into contact with a connectingpart (contact point) between the electric wire and the terminal,oxidation of a metal surface of the electric wire and/or the terminalprogresses, and an electric resistance at a connecting part willincrease. When metals used for the electric wire and the terminal aredifferent from each other, galvanic corrosion progresses. Progression ofmetal oxidation and corrosion at the connecting part causes a crack anda poor contact at the connecting part, and an influence on a productlife cannot be avoided. Particularly, in recent years, wire harnesseshaving an electric wire made of an aluminum alloy and a terminal basematerial made of a copper alloy are put to practical use, and thusproblems of oxidation and corrosion of the connection part are becomingmore prominent.

In order to prevent corrosion of an aluminum wire at the connectingpart, Japanese Laid-Open Patent Publication No. 2004-199934 disclosesthat the terminal is made of an aluminum alloy of the same material typeas that of a wire conductor to suppress galvanic corrosion which occursin the case of a copper terminal of the related art. However, in a casewhere an aluminum alloy is used for the terminal, strength and springcharacteristics of the terminal per se are not sufficient. Further, inorder to compensate for the above, a structure incorporating a springmade of an iron-based material in the terminal is employed, and thusthere is a problem of galvanic corrosion between a spring member and aterminal base material (aluminum) and a problem of an increasedproduction cost due to time and efforts required for assembling.

Japanese Patent No. 4598039 discloses a configuration in which, in orderto protect a connection part between the electric wire and the terminal,a copper cap is attached to a portion of an aluminum wire where aconductor is exposed. However, there is a problem of an increased volumeof a crimp portion due to an existence of the cap and a problem of a badcrimp connection and an increased production cost due to an increase innumber of parts.

Further, in Japanese Laid-Open Patent Publication No. 2011-222243, amethod of molding an entire crimp connection portion with a resin isemployed, and there is a problem of an increased size of a connectorhousing due to an enlarged mold portion, which makes it difficult tomake the entire wire harness with a high-density and miniaturizedstructure, and a problem that a process of manufacturing a wire harnessand an operation thereof become more complicated. Japanese Laid-OpenPatent Publication No. 2004-207172 discloses employing a method inwhich, in order to shield an aluminum conductor from outside, a metalcap is provided to cover the wire conductor and thereafter a crimp pieceof the terminal is further crimped. However, there is a problem that aprocess of attaching the aforementioned metal cap to each conductorbefore crimping the crimp piece of the terminal metal fitting iscumbersome and a problem of an immersion due to breakage of the metalcap by a wire barrel during crimping.

In view of such a situation, how to avoid oxidization or corrosion of aconnecting part between an electric wire and a terminal base materialand to prevent cracking during crimping and springback after crimping isproblematic. Further, how to maintain strength of a connecting partbetween the electric wire and the terminal and to increase durabilityand reliability thereof, while preventing the connecting part fromhaving an increased size as well as preventing a complicated connectingprocess and an increased cost, is problematic. Herein, “springback” is aphenomenon in which a deformed portion tends to return to its originalshape. As for the terminal, it is a phenomenon in which a deformedportion of a tubular crimp portion that is crimp connected with theelectric wire tends to return to its original shape by an elastic forceor the like. When springback occurs in the crimp portion of theterminal, a gap is produced between an inner surface of the tubularcrimp portion and the electric wire. This not only causes a contactfailure between the electric wire and the terminal but also allowsintrusion of moisture into the gap, and may cause corrosion.

SUMMARY

The present disclosure is directed to solving the problems describedabove, and it is an object of the present disclosure to provide aterminal in which cracking during crimp connecting an electric wire andthe terminal and springback after crimp connecting do not occur andhaving an improved anticorrosion property, a method of manufacturingthereof, and a termination connection structure of an electric wire.Further, it is an object of the present disclosure to provide a terminalin which the size of a connecting part and man-hours and a cost of aconnecting process can be reduced, and a manufacturing method thereof.

In order to solve the aforementioned problems, as a basic structure ofthe terminal of the present disclosure, a structure is employed in whicha crimp portion of the terminal is welded to form a tubular crimpportion and an electric wire is inserted into the tubular crimp portionand crimped, and the wire conductor is shielded from outside withoutenlarging the crimp portion. Also, concerning the processing speed andthe cost, it is preferable to employ laser welding for forming thetubular crimp portion of the terminal. As a metal base materialconstituting a metal member of the terminal, copper or a copper alloy isnormally used, but aluminum or an aluminum alloy may be used.

A terminal according to the present disclosure includes a tubular crimpportion that crimp connects with an electric wire, the tubular crimpportion being composed of a metal member, the tubular crimp portionincluding a non-weld portion and a weld portion, the weld portion beingformed by laser welding, wherein a metal base material constituting themetal member of the non-weld portion includes an annealed portion.Further, it is desirable that the annealed portion has a hardness of 70to 90% of a hardness of the non-weld portion other than the annealedportion. Further, it is preferable that, in a cross sectionperpendicular to a longitudinal direction of the tubular crimp portion,an area of the annealed portion is 5 to 60% of an area of the weldportion and the non-weld portion.

It is preferable that the terminal according to the present disclosureis configured such that, in a cross section perpendicular to alongitudinal direction of the tubular crimp portion, an area of the weldportion is 2 to 5% of an area of the non-weld portion.

It is preferable that the terminal according to the present disclosureis configured such that a ratio of a hardness of the non-weld portionother than the annealed portion with respect to a hardness of the weldportion is 2.1 to 2.7.

A method of manufacturing a terminal includes forming a crimp portionhaving a C-shape in a cross section perpendicular to a longitudinaldirection of the tubular crimp portion by bending a metal member, andforming the tubular crimp portion by laser welding both ends of thecrimp portion, wherein, by the welding, a weld portion is formed in thetubular crimp portion, and an annealed portion are formed in a metalbase material constituting the metal member of a non-weld portion.Further, it is preferable that the annealed portion has a hardness of 70to 90% of a hardness of the non-weld portion other than the annealedportion. Further, it is preferable that a tubular crimp portion isformed by welding such that, in a cross section perpendicular to alongitudinal direction of the tubular crimp portion, an area of theannealed portion is 5 to 60% of an area of the weld portion and thenon-weld portion. Note that, the metal base material constituting themetal member may be composed of a plurality of metal base materials,and, in such a case, the plurality of metal base materials may be weldedby a suitable welding unit.

With the method of manufacturing a terminal according to the presentdisclosure, it is preferable that a tubular crimp portion of theterminal is formed by welding such that, in a cross sectionperpendicular to a longitudinal direction of the tubular crimp portion,an area of the weld portion is 2 to 5% of an area of the non-weldportion.

With the method of manufacturing a terminal according to the presentdisclosure, it is preferable that the tubular crimp portion of theterminal is formed by welding such that a ratio of the hardness of thenon-weld portion other than the annealed portion with respect to thehardness of the weld portion is 2.1 to 2.7.

With the method of manufacturing a terminal according to the presentdisclosure, considering a process speed and a cost point, it ispreferable that laser welding is employed in forming a tubular crimpportion of the terminal. Further, as a metal base material constitutinga metal member of the terminal, copper or a copper alloy is normallyused, aluminum or an aluminum alloy may be used.

According to a termination connection structure of an electric wire ofthe present disclosure, a terminal of the present disclosure and anelectric wire are crimp connected at the tubular crimp portion of theterminal. Further, the electric wire may be made of one of copper and acopper alloy, and may be one of aluminum and an aluminum alloy, andother metal.

With a basic structure of a terminal of the present disclosure, moisturefrom outside can be prevented from coming into contact with a contactpoint between an electric wire and a terminal base material, and itbecomes possible to reduce oxidation and corrosion of a metalconstituting the electric wire and the terminal. Since the terminal ofthe present disclosure has an annealed portion, cracking during thecrimping and springback after crimping of the tubular crimp portion canbe reduced and it becomes possible to increase durability andreliability of the terminal having the tubular crimp portion. A furtherpreferable effect can be achieved when an annealed portion of a terminalof the present disclosure has a hardness of 70 to 90% of a hardness ofthe normal portion. Also, a preferable effect can be achieved when, in across section perpendicular to a longitudinal direction of the tubularcrimp portion, an area of the annealed portion is 5 to 60% of an area ofthe weld portion and the non-weld portion.

With the crimp portion of a terminal of present disclosure being weldedin such a manner that a ratio of area of a weld portion with respect toa non-weld portion is within a predetermined range, it becomes possibleto prevent cracking in a tubular crimp portion during crimping and toimprove durability and reliability of a terminal having a tubular crimpportion. Further, with the crimp portion of a terminal of presentdisclosure being welded in such a manner that a ratio of a hardness ofthe normal portion with respect to a hardness of the weld portion iswithin a predetermined range, it becomes possible to prevent cracking ina tubular crimp portion and to improve durability and reliability of theterminal having the tubular crimp portion. Further, by employing theterminal of the present disclosure, a size and cost of a connecting partcan be reduced. Note that, as described below, hardness may be expressedby units such as Vickers hardness or any other suitable units.

With the method of manufacturing the terminal of the present disclosure,since the terminal forms an annealed portion, cracking during crimpingand springback after crimping of the tubular crimp portion can beprevented and it becomes possible to increase durability and reliabilityof the terminal having the tubular crimp portion. A further preferableeffect is obtained by having a hardness of 70 to 90% of a hardness ofthe normal portion, and a further preferable effect is obtained byperforming the welding in such a manner that, in a cross section whichis perpendicular to a longitudinal direction of the tubular crimpportion, an area of the annealed portion of the metal base material is 5to 60% of an area of the weld portion and the non-weld portion. Further,with the method of manufacturing the terminal of the present disclosure,an annealing process can be performed simultaneously with the formationof the tubular crimp portion by welding and the formation of theannealed portion of the tubular crimp portion can be performed in asingle step, thus resulting in a reduction of the production cost.

With a method of manufacturing the terminal of the present disclosure,since welding is performed in such a manner that an area ratio of theweld portion to the non-weld portion is within a predetermined rangewhen forming the tubular crimp portion by welding, cracking of theterminal during crimping can be prevented and it becomes possible toimprove durability and reliability of the terminal. Further, with amethod of manufacturing the terminal of the present disclosure, sincewelding is performed in such a manner that a ratio of the hardness ofthe normal portion to the hardness of the weld portion is within apredetermined range when forming the tubular crimp portion by welding,cracking of the terminal during crimping can be prevented and it becomespossible to improve durability and reliability of the terminal. Also,with a method of manufacturing the terminal of the present disclosure,the connecting process can be prevented from becoming complicated orhaving an increased cost.

Further, with the termination connection structure of the electric wireof the present disclosure, the tubular crimp portion can preventmoisture from outside from coming into contact with a contact pointbetween the electric wire and the metal base material in a state wherethe electric wire and the terminal are in contact by crimping, andoxidation and galvanic corrosion of the metals constituting the electricwire and the terminal can be prevented. Since the terminal of thepresent disclosure can prevent cracking during crimping and springbackafter crimping of the tubular crimp portion, a wire harness havinganticorrosion property and reliability can be provided by using atermination connection structure of the electric wire of the presentdisclosure and assembling the wires.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view showing an embodiment of a terminal of thepresent disclosure.

FIG. 2 is a perspective view showing a termination connection structureof an electric wire of the present disclosure.

FIG. 3 is a perspective view schematically showing a state during themanufacture of the terminal of the present disclosure.

FIG. 4 is a cross-sectional view showing a cross section perpendicularto a longitudinal direction of a tubular crimp portion of the terminalof the present disclosure.

FIG. 5 is a cross-sectional view showing a cross section parallel to thelongitudinal direction of the tubular crimp portion of the terminal ofthe present disclosure.

FIG. 6 is an image of a cross section perpendicular to the longitudinaldirection of the tubular crimp portion of the terminal of the presentdisclosure.

FIG. 7 is a cross-sectional view showing a cross section perpendicularto the longitudinal direction of the tubular crimp portion of theterminal of the present disclosure.

FIG. 8 is a perspective view showing another embodiment of the terminalof the present disclosure.

DETAILED DESCRIPTION

Embodiments of the present disclosure will be described with referenceto the drawings. The embodiment described below is an example, and thescope of the invention is not limited to the embodiment and may alsoencompass other embodiments.

FIG. 1 shows an example of a basic configuration of a terminal 1 of thepresent disclosure. The terminal 1 has a connector portion 20 and atubular crimp portion 30, as well as a transition portion 40 thatbridges them. Further, since the tubular crimp portion 30 of theterminal 1 is formed by welding, a weld portion 70 (in FIG. 1, a hatchedportion) is formed in the tubular crimp portion. The terminal 1 isfabricated from a metal member to ensure conductivity and strength. Themetal member includes a base material made of a metal material (copper,aluminum, iron or alloys containing them as main components) and aplating portion optionally provided on a surface thereof. The platingportion may be provided on all or a part of the metal base material anda noble metal plating such as a tin plating or a silver plating ispreferable. The plating portion may be further provided with anundercoating such as iron (Fe), nickel (Ni) and cobalt (Co), and alloyshaving such elements as main components. In consideration of theprotection and the cost of the metal base material, the plating portionhas a plating thickness of normally 0.3 micrometers (μm) to 1.2micrometers (μm). An electric wire 60 includes an insulating coating 61and a metal core wire (not shown). The electric wire 60 may be a barewire, but an insulated coated wire is normally used as a wire harness.When manufacturing a termination connection structure 10 of the electricwire, the tubular crimp portion 30 of the terminal 1 and the electricwire 60 are crimped with a special jig, a pressing machine, or the like.At this time, an entirety of the tubular crimp portion 30 may be reducedin its diameter, and the tubular crimp portion may be crimped by beingpartly pressed strongly into a recessed shape.

The connector portion 20 is a box portion that permits, for example,insertion of an insertion tab of a male terminal or the like. In thepresent disclosure, a shape of a detailed portion of such a box portionis not particularly limited. For example, as shown in FIG. 8, anotherembodiment of the terminal of the present disclosure may be a structurehaving an insertion tab 11 of a male terminal. In the presentembodiment, an example of a female terminal is shown for the sake ofconvenience of describing the terminal of the present disclosure.

The tubular crimp portion 30 is a portion that crimp connects theterminal 1 and an electric wire. One end thereof has an insertionopening 31 through which an electric wire can be inserted, and anotherend thereof is connected to the transition portion 40. In order toprevent intrusion of moisture or the like, it is preferable that atransition portion 40 side of the tubular crimp portion 30 has a closedend. A method of closing an end may be, for example, laser welding andpress molding. However, when an end on the transition portion side isclosed, a border between the tubular crimp portion 30 and the transitionportion 40 becomes particularly ambiguous. Accordingly, in the presentapplication, a portion from a part at which a core wire and a terminalbase material are crimped to an insertion opening is referred to as thetubular crimp portion. The tubular crimp portion of the terminal of thepresent disclosure can achieve a certain effect against corrosion aslong as it is tubular, and thus its shape and size may vary along itslongitudinal direction.

As the core wire of the electric wire, copper alloy wires, aluminumalloy wires and the like are put into practical use. As an example ofthe aluminum alloy core wire, an aluminum core wire consisting ofapproximately 0.2 mass % iron (Fe), approximately 0.2 mass % copper(Cu), approximately 0.1 mass % magnesium (Mg), approximately 0.04 mass %silicon (Si), and a balance consisting of aluminum (Al) and incidentalimpurities, can be used. Other alloy compositions which may be used arean alloy composition consisting of approximately 1.05 mass % Fe,approximately 0.15 mass % Mg, approximately 0.04 mass % Si, and abalance consisting of Al and incidental impurities, an alloy compositionconsisting of approximately 1.0 mass % Fe, approximately 0.04 mass % Si,and a balance consisting of Al and incidental impurities, and an alloycomposition consisting of approximately 0.2 mass % Fe, approximately 0.7mass % Mg, approximately 0.7 mass % Si, and a balance consisting of Aland incidental impurities. These may further contain alloy elements suchas Ti, Zr, Sn, and Mn. Using a metal core wire of such a composition, acore wire having a total cross section of 0.5 to 2.5 sq (mm²) with 7 to19 twisted core wires can be employed. As a coating material of the corewire, for example, those having polyolefin such as PE and PP as a maincomponent, those having PVC as a main component, or the like, may beused.

At the tubular crimp portion 30, the metal member constituting thetubular crimp portion and the electric wire are crimp connected tothereby realize a mechanical connection and an electrical connection.The tubular crimp portion 30 needs to be designed to have a certain wallthickness to enable crimp connection. FIG. 2 shows a terminationconnection structure 10 of the electric wire of the present disclosure.The termination connection structure 10 has a structure in which theterminal 1 of the present disclosure and the electric wire 60 areconnected. In the termination connection structure 10, the terminal 1and the electric wire 60 are crimp connected with the tubular crimpportion 30. By bundling a plurality of such connection structures, it ispossible to obtain, for example, an automotive wire harness.

FIG. 3 is a diagram schematically showing a state during the manufactureof the terminal 1 of the present disclosure. FL in FIG. 3 represents afiber laser welding apparatus. Fiber laser light L emitted from thewelding apparatus FL is irradiated to weld an un-weld portion 37 of themetal member constituting the tubular crimp portion 30. As describedbelow, in a metal member constituting the tubular crimp portion 30, theweld portion 70 is formed by welding, and in the metal base material onboth sides thereof, an annealed portion 80 is formed due to an influenceof heat during the welding. The annealed portion 80 is a portion thathas a structure which is softer than the terminal base material. Theannealed portion also includes a so-called HAZ (Heat Affected Zone). Inthe metal base material of the tubular crimp portion 30, a portion otherthan the weld portion 70 and the annealed portion 80, that is to say,the non-weld portion 100 other than the annealed portion 80 is referredto as a normal portion 90. As opposed to the weld portion 70 of themetal member, a portion constituted by the normal portion 90 and theannealed portion 80 as well as a plating portion optionally provided onsurfaces thereof is referred to as a non-weld portion 100 of the metalmember. FIG. 1 mentioned above shows the terminal 1 of the presentdisclosure after the welding using the fiber laser welding apparatus hasbeen completed. During the laser welding, the weld portion 70 shown inFIG. 1 can be formed as, for example, a generally linear region from thetransition portion 40 to the insertion opening 31 of the electric wire.The weld portion 70 is formed by the metal member (the base material andthe plating portion) which is once melted by heat from the laser andthereafter solidified. Usually, a size of a crystal grain thereof islarger than that of the non-weld portion 100. The plating metal that wasconstituting the plating portion may melt into the weld portion 70. Notethat, the welding by the aforementioned fiber laser welding apparatus isdescribed as an example of the welding method and may be other weldingmethod as long as it does not depart from the present disclosure.

As shown in FIG. 7, a portion having a hardness of 70 to 90% of thehardness of the normal portion 90 is formed in the annealed portion 80of the metal base material of the non-weld portion 100 and such aportion is referred to as an annealed portion 50 of the metal basematerial (hereinafter, such a portion of the annealed portion 80 isreferred to as an annealed portion 50). When crimp connecting theelectric wire 60 and the tubular crimp portion 30, the annealed portion80 of the metal base material exerts a buffer effect to the deformationof the terminal 1. Normally, the base material constituting the terminal1 has characteristics which remain the same as the characteristics ofthe material itself at the time of manufacture, and it is alsowork-hardened due to further working by terminal shaping or the like.The annealed portion 80 of the metal base material can be transformedwith a stress lower than a stress in the normal portion, since it has asoftened structure obtained by reducing an internal strain from such aworked structure. Also, an amount that can deform plastically is greaterthan that of the normal portion. In other words, when crimp connectingthe electric wire, since the annealed portion 80 has a buffer effect ona stress in the terminal base material, deformation into a desired shapeis facilitated and a good workability is obtained.

Note that, the annealed portion 80 (the annealed portion 50) does notnecessarily have to be provided over an entirety of the tubular crimpportion 30. This is because with the existence of the annealed portion,workability becomes good and an effect of reducing the springback isobtained. Therefore, the annealed portion may be provided only at a partof the tubular crimp portion 30. Preferably, it is provided in thevicinity of a connecting part between the core wire and the tubularcrimp portion of the wire that is a part where an amount of working isthe greatest. The annealed portions are preferably providedsubstantially symmetrical about the weld portion in a cross sectionperpendicular to the longitudinal direction.

Although it depends on the kind of metal base material constituting themetal member of the terminal 1, in a case where the base material ismade of a copper alloy or an aluminum alloy, the annealed portion 80 canbe provided by increasing the temperature to 500° C. or above.Specifically, if it is possible to apply a heat treatment such that thetemperature of a predetermined region of the tubular crimp portion 30can be increased to 500° C. or above and maintained for a predeterminedtime, as necessary, the annealed portion 80 is formed. The settings ofthe temperature and the maintaining time are determined such that apredetermined hardness of the annealed portion 50 is obtained. It isnecessary to perform heat treatment under a condition that the annealedportion 80 has a predetermined area ratio with respect to the tubularcrimp portion in a cross sectional view perpendicular to thelongitudinal direction of the tubular crimp portion 30. The temperaturerange for providing an annealed portion may be a temperature range belowand above 500° C. within which the shape and the function as a terminalare not lost.

FIG. 7 is a cross-sectional view perpendicular to the longitudinaldirection of the tubular crimp portion 30. In a cross sectionperpendicular to the longitudinal direction of the tubular crimp portion30 of the terminal 1 of the present disclosure, the annealed portion 50(hatched portion) is formed that has a hardness of 70 to 90% of thehardness of the normal portion 90 of the metal base materialconstituting a metal member 32. Such an annealed portion 50 is formed inthe annealed portion 80 of the non-weld portion 100. The formation ofthis annealed portion may be performed by separately performing anannealing process in addition to laser welding for forming the tubularcrimp portion. In the tubular crimp portion 30 of the terminal 1 of thepresent disclosure, as shown in FIG. 7, an area of the region of thisannealed portion 50 has an area of 5 to 60% of the area of the weldportion 70 and the non-weld portion 100 in the cross sectionperpendicular to the longitudinal direction. It was seen that, when theannealed portion 50 takes such a value of the area ratio, crackingduring crimping and an amount of springback after crimping of thetubular crimp portion 30 decrease as described below. Note that the arearatio of the annealed portion in a cross sectional view is a valueobtained by dividing a cross sectional area of the region of theannealed portion 50 of the metal base material by a total crosssectional area of the tubular crimp portion 30. For example, in a casewhere the tubular crimp portion 30 is a circular cylinder, the arearatio is 100×((length of annealed portion)×thickness ofboard)/(circumference of tube×thickness of board). Here, thecircumference of the tube is (outer circumference of tube+innercircumference of tube)/2. Note that, C in FIG. 7 indicates a center ofthe tube when the tubular crimp portion 30 is viewed in a cross sectionperpendicular to the longitudinal direction.

In order to calculate the area ratio from the cross section of thetubular crimp portion, it is necessary to determine the region of theannealed portion. However, it is difficult to distinguish between thework structure and the annealed portion at a glance. When it can bedistinguished, an area ratio can be calculated with the aforementionedmethod. However, when it cannot be distinguished, an area ratio can becalculated by measuring the hardness along an entire circumference at apredetermined interval for the metal base material portion in the crosssection of the tubular crimp portion. In this case, a hardness of atleast ten points or more is measured, and the number of points at whichthe hardness is 70 to 90% when the hardness of the metal base materialis taken as 100% is counted. That is to say, in this case, the arearatio of the annealed portion can be obtained by (number of points atwhich the hardness is 70 to 90% of the hardness of the metal basematerial)/(number of points at which measurement was performed). Notethat, the hardness may be measured using hardness tests of Rockwellhardness (HR), Vickers hardness (Hv), Knoop hardness (HN), the Brinellhardness (HB), or the like. Herein, a method of measuring a hardnesswith a Vickers hardness test is taken as an example. Measurement of thehardness is preferably performed by a method in conformity with a normalindustry standard (JIS Z2244 for Vickers test) or the like.

FIG. 4 is a cross-sectional view perpendicular to a longitudinaldirection of the tubular crimp portion 30. The cross section of thetubular crimp portion 30 of the terminal 1 of the present disclosure isconstituted by the metal member 32 having a predetermined wallthickness, and, as has been described above, this can be divided intothe normal portion 90 of the metal base material and the annealedportion 80 of the metal base material which are the non-weld portion100, as well as the weld portion 70, and further the plating portion(not shown) which is optionally provided on a surface of the basematerial. It is desirable that, when it is viewed in a cross sectionperpendicular to the longitudinal direction of the tubular crimp portion30 shown in FIG. 2, welding (e.g., laser welding) is performed in such amanner that the region of the weld portion 70 has an area ratio of 2 to5% of the region of the non-weld portion 100 (the normal portion 90 andthe annealed portion 80, as well as the plating portion optionallyprovided on the surface of metal base material thereof). This is becausetest results obtained showed that cracking in the tubular crimp portion30 during crimping can be prevented when the region of the weld portion70 takes such a value of the area ratio with respect to the region ofthe non-weld portion 100 (see test results and evaluation resultsdescribed below). More desirably, the region of the weld portion 70formed by welding has an area ratio of 2.5 to 3.5% of the region of thenon-weld portion 100 (the normal portion 90 and the annealed portion 80,as well as the plating portion optionally provided on a surface of thesemetal base material). Even more desirably, the region of the weldportion 70 formed by welding has an area ratio of approximately 3% ofthe region of the non-weld portion 100 (the normal portion 90 and theannealed portion 80, as well as the plating portion optionally providedon a surface of these metal base material). Note that, these can beperformed with or without the formation of the annealed portion havingthe aforementioned predetermined area ratio.

Note that, the area ratio of the weld portion 70 of the tubular crimpportion 30 when viewed in a cross section is obtained by dividing across sectional area of the region of the weld portion 70 by that of theregion of the non-weld portion 100. For example, in a case where thetubular crimp portion 30 is a circular cylinder, the area ratio is100×((length of weld portion 70×board thickness)/((circumference of tubeof tubular crimp portion 30×board thickness)−(length of weld portion70×board thickness))). Here, as for the circumference of the tube of thetubular crimp portion 30, the circumference is (outer circumference oftube+inner circumference of tube)/2. Note that, C in FIG. 4 shows acenter when the tubular crimp portion 30 is viewed in a cross sectionperpendicular to the longitudinal direction.

In order to calculate an area ratio from the cross section of thetubular crimp portion 30, it is necessary to discriminate between theregion of the weld portion 70 and the region of the non-weld portion100. The discrimination can be performed by, for example, observing anSEM (Scanning Electron Microscope) image of the cross section of thetubular crimp portion 30 and identifying the weld portion 70 and thenon-weld portion 100. In that case, discrimination is made possible byetching the cross section of the tubular crimp portion 30. An examplethereof is shown in FIG. 6. FIG. 6 is a cross sectional photographicimage showing a state in which the weld portion 70 and the annealedportion 80 are respectively formed in the tubular crimp portion 30 afterthe welding. By using such a photographic image, each portion can beidentified. As another discrimination method, a method of discriminatingthe weld portion and the non-weld portion by measuring the hardnessalong an entire circumference at a predetermined interval for the metalbase material portion of the cross section of the tubular crimp portion30 and calculating the area ratio is conceivable. In this case, forexample, a method is employed in which at least ten points or more aremeasured, and the weld portion 70 and the non-weld portion 100 arediscriminated using the value of hardness. As has been described above,the hardness may be measured using hardness tests such as Rockwellhardness (HR), Vickers hardness (Hv), Knoop hardness (HN), the Brinellhardness (HB).

It is desirable that in a cross section perpendicular to thepredetermined longitudinal direction of the tubular crimp portion 30shown in FIG. 2, laser welding is performed in such a manner that theratio of the hardness of the region of the normal portion 90 withrespect to the hardness of the region of the weld portion 70 is 2.1 to2.7. This is because the test results obtained showed that cracking inthe tubular crimp portion 30 during crimping can be prevented when theratio of hardness of the region of the normal portion with respect tothe hardness of the region of the weld portion 70 takes such a range ofvalues (see test results and evaluation results described below). Moredesirably, it is a case where the ratio of the hardness of the region ofthe normal portion 90 with respect to the hardness of the region of theweld portion 70 formed by welding is 2.2 to 2.5. Even more desirably, itis a case where the ratio of the hardness of the region of the normalportion 90 of the non-weld portion 100 with respect to the hardness ofthe region of the weld portion 70 formed by welding is 2.3 to 2.4. Thesecan be performed whether the annealed portion having an aforementionedpredetermined area ratio is formed or not.

With reference to FIG. 4, viewing in a cross section perpendicular tothe longitudinal direction of the tubular crimp portion 30, for the sakeof convenience, the hardness of the weld portion 70 is a hardness at acenter position of the weld portion 70 (a center point of the weldportion 30 on a broken line passing through the weld portion 30 in FIG.4), and the hardness of the normal portion 90 is a hardness at aposition of the normal portion 90 which is at approximately 180 degreesin a peripheral direction from the center position of the weld portion70 (e.g., a center point of the normal portion on a broken line passingthrough the normal portion in FIG. 4). The measuring point of thehardness may be other position in the weld portion 70 and the normalportion 90. C in FIG. 4 shows the center when the tubular crimp portion30 is viewed in a cross section perpendicular to the longitudinaldirection.

As has been described above, discrimination between the region of theweld portion 70 and the region of the non-weld portion 100 of thetubular crimp portion 30 is performed by, for example, observing an SEM(Scanning Electron Microscope) image of the cross section of the tubularcrimp portion 30 and identifying the weld portion 70 and the non-weldportion 100. In that case, discrimination is made possible by etchingthe cross section of the tubular crimp portion 30. An example thereof isshown in FIG. 6. FIG. 6 shows a state in which the weld portion 70 andthe annealed portion 80 are respectively formed in the tubular crimpportion 30 after the welding. By using such an image, each portion canbe identified. As another discrimination method, a method ofdiscriminating the weld portion and the non-weld portion by measuringthe hardness along an entire circumference at a predetermined intervalfor the metal base material portion of the cross section of the tubularcrimp portion 30 and calculating the area ratio is conceivable. In thiscase, for example, a method in which a hardness of at least ten pointsor more is measured and the weld portion 70 and the non-weld portion 100are discriminated using the value of hardness is conceivable.

Hereinafter, a manufacturing method of the terminal 1 of the presentdisclosure will be described. Since the terminal 1 of the presentdisclosure is a terminal that has the tubular crimp portion 30 and hasthe annealed portion in the tubular crimp portion 30, the manufacturingmethod is not limited as long as such a configuration can be achieved.

For the manufacturing of the terminal 1 of the present disclosure, ametal member is used which is optionally provided with a plating portionon a surface of a metal base material (a copper alloy, an aluminum alloyand an iron alloy). A strip (board) of such a metal member is punchedinto a shape of a terminal unfolded into a planar development and acrimp portion is provided by bending. At this time, the crimp portiongenerally has a C-shaped cross section due to the bending from a flatplane, and becomes a tubular crimp portion by joining an open part bywelding. As a preferred manufacturing method of the terminal 1 of thepresent disclosure, the tubular crimp portion 30 is laser welded by afiber laser.

Since copper and a copper alloy have bad absorption efficiency for heatproduced by laser light irradiation, the weld portion and the annealedportion might not be provided suitably when these are used as the metalbase material. This problem is overcome by using a laser light having ahigh energy density such as a fiber laser light. With the welding by thefiber laser light having a high energy density, the annealed portion 80can be provided in the metal base material while forming the tubularcrimp portion 30. Thus, since the tubular crimp portion 30 and theannealed portion 80 can be provided in one step, the terminal 1 of thepresent disclosure can be manufactured efficiently. This is similar forthe annealed portion 50.

In the terminal 1 of the present disclosure, the tubular crimp portion30 may be formed with a different welding unit. In such a case, sincethe annealed portion 80, 50 may not be formed suitably, it is necessaryto apply partial heat treatment and cooling to the tubular crimp portion30 in such a case.

FIG. 3 is a view schematically showing a state during manufacturing ofthe terminal 1 of the present disclosure. FL in FIG. 3 represents afiber laser welding apparatus. Fiber laser light L emitted from thewelding apparatus FL is irradiated to weld an un-weld portion 37 of themetal member constituting the tubular crimp portion 30. With the heatdue to the welding, an annealed portion 80 is formed in the metal basematerial constituting the tubular crimp portion 30. The annealed portion80 can be provided by a heat treatment of 500° C. or above. However, ifthe fiber laser light L having an excessively high energy density isused, the annealed portion is formed in a broader extent than necessaryand the entire tubular crimp portion 30 softens. Therefore, it ispreferable that the welding is performed with the fiber laser light Lhaving an output power of 150 to 500 W. The annealed portion 80 can beprovided in an appropriate extent by adjusting a laser power and a sweeprate.

The manufacturing method of the terminal 1 of the present disclosure isa method of manufacturing a terminal in which, when forming the tubularcrimp portion 30 by welding (e.g., laser welding), in addition to oralternatively to the above, welding is performed in such a manner thatthe weld portion 70 of a predetermined size is formed in the tubularcrimp portion 30 (see FIG. 1). Also, manufacturing method of theterminal 1 of the present disclosure is a method of manufacturing aterminal in which, when forming the tubular crimp portion 30 by welding,in addition to or alternatively to the above, welding is performed insuch a manner that the weld portion 70 having a predetermined hardnessis formed in the tubular crimp portion 30 (see FIG. 1). As a method offorming the tubular crimp portion 30, laser welding or other weldingmethod is conceivable.

The manufacturing method of the terminal 1 of the present disclosure isa method in which, when forming the tubular crimp portion of the metalmember by forming a crimp portion having a C-shaped cross section bybending the aforementioned metal member and then welding the crimpportion at opposing ends thereof, the tubular crimp portion 30 is formedby welding in such a manner that the region of the weld portion 70 hasan area ratio of 2 to 5% of the region of the non-weld portion 100 (thenormal portion 90 and the annealed portion 80, and the plating portionoptionally provided on the surface of the metal base material thereof)when viewed in a cross section perpendicular to the longitudinaldirection of the tubular crimp portion 30. As has been described above,this is because the test result showed that cracking during crimping ofthe tubular crimp portion 30 can be prevented when the region of theweld portion 70 takes such a value of area ratio with respect to theregion of the non-weld portion 100.

The manufacturing method of the terminal 1 of the present disclosure is,more desirably, a method in which the tubular crimp portion 30 is formedby welding in such a manner that the region of the weld portion 70 hasan area ratio of 2.5 to 3.5% of the region of the non-weld portion 100(the normal portion 90 and the annealed portion 80, and the platingportion optionally provided on the surface of the metal base materialthereof). Even more desirably, it is a method in which the tubular crimpportion 30 is formed by welding in such a manner that the region of theweld portion 70 has an area ratio of approximately 3% of the region ofthe non-weld portion 100 (the normal portion 90 and the annealed portion80, and the plating portion optionally provided on the surface of themetal base material thereof).

Also, according to the manufacturing method of the terminal 1 of thepresent disclosure, in forming the tubular crimp portion of theterminal, when forming the tubular crimp portion 30 of the metal memberby forming a crimp portion having a C-shaped cross section by bendingthe aforementioned metal member and then welding the crimp portion atopposing ends thereof, the weld portion 70 formed by welding and thenon-weld portion 100 including the normal portion 90 of the metal basematerial, the annealed portion 80 of the metal base material, and theplating portion optionally provided on the surface of the metal basematerial thereof are formed in the tubular crimp portion 30, and themethod is characterized in that the tubular crimp portion 30 of theterminal 1 is formed by welding in such a manner that the ratio of thehardness of the normal portion 90 of the metal base material withrespect to the hardness of the weld portion 70 is 2.1 to 2.7.

The manufacturing method of the terminal 1 of the present disclosure ismore preferable when the tubular crimp portion 30 of the terminal 1 isformed by welding in such a manner that ratio of the hardness of thenormal portion 90 with respect to the hardness of the weld portion 70 is2.2 to 2.5. More preferably, it is a manufacturing method of theterminal in which the tubular crimp portion 30 is formed by welding insuch a manner that a ratio of the hardness of the normal portion 90 withrespect to the hardness of the weld portion 70 is 2.3 to 2.4. As hasbeen described above, for the sake of convenience, the hardness of theweld portion 70 is the hardness at the center position of the weldportion 70, and the hardness of the normal portion 90 is the hardness ateither position of the positions of approximately 180 degrees in aperipheral direction from the center position of the weld portion 70 ofthe normal portion 90 when the tubular crimp portion 30 is viewed in across section perpendicular to the longitudinal direction. The measuringpoint of the hardness may be other positions in the weld portion 70 andthe normal portion 90.

The manufacturing method of the terminal 1 of the present disclosure ispreferably a method of manufacturing the tubular crimp portion 30 bylaser welding by a fiber laser. By using a laser light that has a highenergy density such as a fiber laser light, even with copper or a copperalloy having bad absorption efficiency for heat produced by laser lightirradiation, a weld width and a width of the heat affected zone can bemade smaller. When providing a wire engaging groove in the tubular crimpportion 30, the groove can be provided by partially melting an innerpart of the crimp portion before the laser welding using a fiber laser.

FIG. 5 shows a part of a cross-sectional view parallel to thelongitudinal direction of the tubular crimp portion 30. FIG. 5 shows aconfiguration provided with wire engaging grooves 34 a and 34 b in aninner wall surface 33 of the tubular crimp portion 30. A plating such astin or silver is usually applied at a part where the core wire of theelectric wire and the metal member come into contact. Particularly, whenthe electric wire made of a core wire of aluminum or an aluminum alloyis used, since aluminum or an aluminum alloy has a greater contactresistance against tin as compared to copper or a copper alloy, acontact pressure can be maintained well and it becomes possible toimprove electric performance by providing the wire engaging grooves 34 aand 34 b in the tubular crimp portion 30. In FIG. 5, the wire engaginggroove 34 a is formed as a groove having a rectangular cross section,and the wire engaging groove 34 b is formed as a groove having asemicircular cross section. These wire engaging grooves can be formed byprocessing the metal member before forming the tubular crimp portion 30.Also, these wire engaging grooves can be provided by cutting or the likeby a fiber laser and a machine. Such grooves are also referred to asserrations, and can be formed in an inner wall surface 33 of the metalmember of the tubular crimp portion 30 as necessary.

FIG. 2 shows the termination connection structure 10 of the electricwire of the present disclosure. The termination connection structure 10has a structure in which the terminal 1 of the present disclosure and anelectric wire (electric wire 60) are connected. As for the terminationconnection structure 10, the terminal 1 and the electric wire 60 arecrimp connected by the tubular crimp portion 30. A manner in which thecrimp connection is not particularly limited, but in FIG. 2, a firstcrimp deformation portion 35 and a second crimp deformation portion 36are provided. Usually, when an electric wire and a terminal basematerial are worked for crimp connection, the tubular crimp portion 30is plastically deformed and crimp connected with the electric wire 60.In the example shown in FIG. 2, the first crimp deformation portion 35is the portion where an amount of deformation is the greatest. In thismanner, crimp connection may be performed in two steps of deformation.Note that, the processing may be not only a deformation process such asdiameter reduction, but may also be deformation of the tubular crimpportion into an irregular shape.

When manufacturing the termination connection structure 10 of theelectric wire, crimp connection that positively causes plasticdeformation of the annealed portion 80, 50 of the metal base material ofthe tubular crimp portion 30 is preferable. When crimp connecting thetubular crimp portion 30 of the terminal 1 and the electric wire 60, itis performed with an exclusive jig or a press machine. In such a case,crimping may be performed by diameter reduction on the entire tubularcrimp portion 30 and there may also be a case in which the tubular crimpportion is crimped by partially performing a strong working into arecessed shaped. In such a case, a position is preferably adjusted insuch a manner that an amount of plastic deformation of the annealedportion 80, 50 becomes greater. In other words, by adjusting a tip of aprotruded portion formed during press machining to come directly above(outer side) the annealed portion 80, 50, an amount of deformation ofthe annealed portion 80, 50 becomes greater. In this manner, since theannealed portion 80, 50 of the metal base material that is relativelysoft can take up most of the part of the plastic deformation, it cancontribute to the reduction of the springback.

EXAMPLES

Hereinafter, test results and evaluation results of the presentdisclosure will be shown. Note that the present disclosure is notlimited to examples related to the following tests.

A first example will be described. In the first example, a copper alloyboard FAS-680 (thickness 0.25 mm, H material) manufactured by FurukawaElectric Co., Ltd. was used as the metal base material of the terminal.FAS-680 is an alloy having a composition containing 2.0 to 2.8 mass %nickel (Ni), 0.45 to 0.6 mass % silicon (Si), 0.4 to 0.55 mass % zinc(Zn), 0.1 to 0.25 mass % tin (Sn), 0.05 to 0.2 mass % magnesium (Mg),and the balance is copper (Cu) and incidental impurities. FAS-680 has aVickers hardness of approximately 200 Hv. At least at a part of themetal base material in which the weld portion was formed, a metal memberon which a tin plating was applied was used as a plating portion.

The core wire of the aluminum wire was an aluminum alloy MSA1 (wire,wire size 0.43 mm) manufactured by Furukawa Electric Co., Ltd. MSA1 isan alloy having a composition of approximately 0.2% iron (Fe),approximately 0.2% copper (Cu), approximately 0.1% magnesium (Mg),approximately 0.04% silicon (Si), and the balance is aluminum (Al) andincidental impurities. A 2.5 sq, 19 strand twisted wire was made usingMSA1.

An un-weld portion of the crimp portion formed in a C-shape was weldedby laser welding to form a tubular crimp portion. By this welding, theannealed portion was obtained in the metal base material of the tubularcrimp portion. Also, the number of wire engaging portions and thehardness of the annealed portion were changed by changing variousconditions. Note that, as for the one provided with wire engaginggrooves (serrations), the grooves were provided by partially melting aninner side of the tubular crimp portion by a fiber laser in advancebefore laser welding. In this case, it is likely that the groove has asemicircular shape when viewed in a cross section in the longitudinaldirection of the tubular crimp portion (FIG. 5, the shape of 34 b).

Making the end portions of the non-weld portion of the metal member tobutt with each other and welding the butted portion is referred to as“butt welding”. Making the end portions of the non-weld portion of themetal member to overlap with each other and welding the overlappedportion is referred to as “lapped welding”. Providing an un-weld portionof the metal member at an angle with respect to the longitudinaldirection of the terminal and welding along this is referred to as“angled welding”. The welding of the tubular crimp portion may be any ofthese methods and may be any other appropriate method.

Experiment conditions are as follows:

-   -   Laser source used: 500 W CW fiber laser ASF1J233 (wavelength        1,084 nm single-mode oscillation laser light) manufactured by        Furukawa Electric Co., Ltd.    -   Sweep irradiation using a galvano scanner (non-telecentric)    -   Laser light power: 300, 400, 500 W    -   Sweep rate: 90, 135, 180 mm/sec.    -   Sweep distance: 9 mm    -   Laser light irradiation with all conditions focused (spot size:        0.02 mm)

As for the tubular crimp portion of the terminal manufactured under theaforementioned conditions, an area ratio of the annealed portion havinga Vickers hardness of 70 to 90% of a copper alloy board FAS-680 in across section perpendicular to the longitudinal direction of the tubularcrimp portion was observed. In order to calculate the area ratio, thetubular crimp portion was cut perpendicularly to the longitudinaldirection, and the Vickers hardness was measured at a certain intervalfor an entire periphery for its O-shaped cross section. Note that,measurement was performed at least at ten points or more. In thisexample, 20 points or more were measured if possible. Also, measurementswere made substantially at the center point of the thickness of the basematerial. The Vickers hardness was measured in conformity with JIS Z2244. Then, the area ratio was obtained by dividing “the number ofpoints at which the Vickers hardness is 70 to 90% of the hardness of thebase material metal” by “the number of measurement points”.

An environmental test was performed on the obtained samples. Thereafter,the termination connection structure of the electric wire as shown inFIG. 4 was manufactured, and corrosive property was evaluated bycross-sectional observation of an amount of corrosion of an aluminumwire of the crimp portion using an optical microscope. Evaluationresults are indicated using the following symbols. Symbol ⊚ denotes thataluminum wire remains without corrosion. Symbol ◯ denotes that somecorrosion (spot-like corrosion and pitting corrosion) was observed in anouter periphery of the aluminum. Symbol Δ denotes that 50% or more arearatio of the aluminum wire remained. Symbol x denotes that 50% or morearea ratio of aluminum disappeared.

The workability was evaluated using crack appearance after crimping.Evaluation was made by observing the surface and the cross section ofthe tubular crimp portion with an electron microscope such as an SEM(Scanning Electron Microscope). Symbol ⊚ denotes that no creases or thelike were observed. Symbol ◯ denotes that creases were observed but withno cracks were produced. Symbol Δ denotes that cracks were produced butonly superficially. Symbol x denotes that cracks penetrating through thebase material were produced.

The springback was evaluated by comparing a resistance value of the corewire of the electric wire 10 cm away from a wire insertion opening ofthe tubular crimp portion of the terminal immediately after the crimpingwith a resistance value at the same position after letting stand for oneweek in an indoor environment. It is known that when a springbackoccurs, a contact pressure at a contact part between the electric wireand the metal member decreases and thus a resistance value of theelectric wire increases. Therefore, an amount of increase in theresistance value of the electric wire was evaluated as an evaluation ofthe springback. The resistance value was measured using Hioki 3560 ACMilliohm HiTester.

The environmental test was carried out with the following procedure. Asample terminal was inserted into a cavity space, and set in each testdevice such that an electric wire-side faces the ceiling and aterminal-side faces the ground, and such that the cavity space issuspended in the air. Note that (2) is performed immediately after (1)without washing.

(1) Salt Spray Test: 5 mass % salt water, 35° C., let stand for 96 hours

(2) Moist-Heat Shelf Test: Let stand for 96 hours in an environment oftemperature 80° C. and room humidity (RH) 95%.

(3) Rinse in water (ion exchanged water)

(4) Drying

The aforementioned various test results and evaluation results are shownin Tables 1-1 to 1-3.

TABLE 1-1 SAMPLE CONDITION LASER WELDING SERRATION AREA RATIO OF VICKERSHARDNESS CONDITION (NUMBER OF ANNEALED PORTION IN Hv HOW TO LASER SWEEPSERRATIONS) CROSS-SECTIONAL TERMINAL BASE SET PRIOR POWER RATE CRIMPREAR END OBSERVATION BASE ANNEALED MATERIAL TO WELDING (W) (mm/sec)PORTION PORTION % MATERIAL PORTION EXAM- FAS-680 BUTTED 300 90 0 0 50220 172 PLE 400 55 204 160 500 60 204 153 300 135 30 210 169 400 35 220161 500 40 204 153 300 180 10 211 157 400 15 213 155 500 20 213 162 30090 1 0 50 212 165 400 55 201 160 500 60 210 170 300 135 30 209 172 40035 208 158 500 40 204 162 300 180 10 220 157 400 15 206 160 500 20 201157 EVALUATION RESULT SPRING-BACK ANTICORROSION EVALUATION PROPERTYDIFFERENCE EVALUATION BETWEEN As AND WORKABILITY AMOUNT OF RESISTANCERESISTANCE EVALUATION CORROSION AFTER mΩ AFTER BEING CRACKINGENVIRONMENTAL As LET STAND AFTER CRIMPING TEST EXAM- 1.71 0.18 Δ ◯ PLE1.74 0.03 ◯ ◯ 1.74 0.19 Δ ◯ 1.74 0.01 ◯ ◯ 1.74 0.03 ⊚ ◯ 1.70 0.02 ◯ ◯1.70 0.11 Δ ◯ 1.71 0.02 ◯ ◯ 1.73 0.14 Δ ◯ 1.64 0.16 Δ ◯ 1.64 0.01 ◯ ◯1.61 0.18 Δ ◯ 1.61 0.03 ◯ ◯ 1.62 0.03 ⊚ ◯ 1.64 0.02 ◯ ◯ 1.64 0.12 Δ ◯1.63 0.03 ◯ ◯ 1.63 0.19 Δ ◯

TABLE 1-2 SAMPLE CONDITION LASER WELDING SERRATION AREA RATIO OF VICKERSHARDNESS CONDITION (NUMBER OF ANNEALED PORTION IN Hv HOW TO LASER SWEEPSERRATIONS) CROSS-SECTIONAL TERMINAL BASE SET PRIOR POWER RATE CRIMPREAR END OBSERVATION BASE ANNEALED MATERIAL TO WELDING (W) (mm/sec)PORTION PORTION % MATERIAL PORTION EXAM- FAS-680 BUTTED 300 90 0 1 50201 166 PLE 400 55 200 161 500 60 201 166 300 135 30 219 168 400 35 215170 500 40 217 164 300 180 10 206 153 400 15 206 156 500 20 206 153 30090 1 1 50 216 165 400 55 200 153 500 60 205 160 300 135 30 210 162 40035 218 164 500 40 204 168 300 180 10 205 172 400 15 218 157 500 20 203157 EVALUATION RESULT SPRING-BACK ANTICORROSION EVALUATION PROPERTYDIFFERENCE EVALUATION BETWEEN As AND WORKABILITY AMOUNT OF RESISTANCERESISTANCE EVALUATION CORROSION AFTER mΩ AFTER BEING CRACKINGENVIRONMENTAL As LET STAND AFTER CRIMPING TEST EXAM- 1.74 0.11 Δ ⊚ PLE1.74 0.03 ◯ ⊚ 1.74 0.17 Δ ⊚ 1.72 0.01 ◯ ⊚ 1.72 0.01 ⊚ ⊚ 1.73 0.02 ◯ ⊚1.72 0.16 Δ ⊚ 1.73 0.03 ◯ ⊚ 1.70 0.11 Δ ⊚ 1.60 0.12 Δ ⊚ 1.61 0.01 ◯ ⊚1.64 0.18 Δ ⊚ 1.62 0.01 ◯ ⊚ 1.61 0.02 ⊚ ⊚ 1.61 0.01 ◯ ⊚ 1.60 0.19 Δ ⊚1.61 0.02 ◯ ⊚ 1.60 0.17 Δ ⊚

TABLE 1-3 SAMPLE CONDITION LASER WELDING SERRATION AREA RATIO OF VICKERSHARDNESS CONDITION (NUMBER OF ANNEALED PORTION IN Hv HOW TO LASER SWEEPSERRATIONS) CROSS-SECTIONAL TERMINAL BASE SET PRIOR POWER RATE CRIMPREAR END OBSERVATION BASE ANNEALED MATERIAL TO WELDING (W) (mm/sec)PORTION PORTION % MATERIAL PORTION EXAM- FAS-680 BUTTED 300  90 2 2 50212 156 PLE 400 55 218 169 500 60 200 163 300 135 30 209 168 400 35 217169 500 40 211 156 300 180 10 216 153 400 15 211 156 500 20 200 171LAPPED 400 135 0 0 35 202 165 1 1 35 206 154 ANGLED 400 135 0 0 35 218157 1 1 35 206 169 COM- F CRIMP — 212 — PAR- BUTTED 300  40 0 0 80 211191 ATIVE 500 230 0 0  5 214  88 EXAM- PLE EVALUATION RESULT SPRING-BACKANTICORROSION EVALUATION PROPERTY DIFFERENCE EVALUATION BETWEEN As ANDWORKABILITY AMOUNT OF RESISTANCE RESISTANCE EVALUATION CORROSION AFTERmΩ AFTER BEING CRACKING ENVIRONMENTAL As LET STAND AFTER CRIMPING TESTEXAM- 1.62 0.15 Δ ⊚ PLE 1.61 0.01 ◯ ⊚ 1.61 0.15 Δ ⊚ 1.62 0.03 ◯ ⊚ 1.610.03 ⊚ ⊚ 1.63 0.02 ◯ ⊚ 1.63 0.14 Δ ⊚ 1.62 0.01 ◯ ⊚ 1.63 0.16 Δ ⊚ 1.740.01 ⊚ Δ 1.71 0.02 ⊚ ◯ 1.71 0.01 ⊚ Δ 1.73 0.03 ⊚ ◯ COM- 1.71 0.01 ⊚ XPAR- 1.70 0.32 X ◯ ATIVE 1.70 0.22 X X EXAM- PLE

Next, a second example will be described. In the second example, ageneral brass material C2600 (strip, thickness 0.25 mm, H material) wasused as the base material of the terminal. The chemical composition ofC2600 is Cu: 68.5 to 71.5 mass %, Pb: less than or equal to 0.05 mass %,Fe: less than or equal to 0.05 mass %, and the balance is Zn andincidental impurities. The Vickers hardness of an H material isapproximately 150 Hv. Note that a least a part of the metal basematerial in which the weld portion was formed was constituted using ametal member on which a tin plating was applied as a plating portion.Other than the above, a terminal having a shape similar to that of thefirst example was constituted and an evaluation similar to that of thefirst example was performed and evaluation results thereof are shown inTables 2-1 to 2-3.

TABLE 2-1 SAMPLE CONDITION LASER WELDING SERRATION AREA RATIO OF VICKERSHARDNESS CONDITION (NUMBER OF ANNEALED PORTION IN Hv HOW TO LASER SWEEPSERRATIONS) CROSS-SECTIONAL TERMINAL BASE SET PRIOR POWER RATE CRIMPREAR END OBSERVATION BASE ANNEALED MATERIAL TO WELDING (W) (mm/sec)PORTION PORTION % MATERIAL PORTION EXAM- C2600 BUTTED 150 150 0 0 40 146131 PLE 250 45 148 123 350 50 147 131 150 200 25 147 127 250 25 148 128350 30 146 126 150 250 10 150 130 250 10 148 130 350 15 145 123 150 1501 0 40 146 127 250 45 146 124 350 50 149 131 150 200 25 149 124 250 25147 127 350 30 150 130 150 250 10 150 128 250 10 145 128 350 15 146 130EVALUATION RESULT SPRING-BACK ANTICORROSION EVALUATION PROPERTYDIFFERENCE EVALUATION BETWEEN As AND WORKABILITY AMOUNT OF RESISTANCERESISTANCE EVALUATION CORROSION AFTER mΩ AFTER BEING CRACKINGENVIRONMENTAL As LET STAND AFTER CRIMPING TEST EXAM- 1.74 0.12 Δ ◯ PLE1.73 0.02 ◯ ◯ 1.74 0.12 Δ ◯ 1.72 0.02 ◯ ◯ 1.74 0.01 ⊚ ◯ 1.71 0.01 ◯ ◯1.70 0.17 Δ ◯ 1.74 0.02 ◯ ◯ 1.74 0.19 Δ ◯ 1.64 0.14 Δ ◯ 1.64 0.03 ◯ ◯1.60 0.18 Δ ◯ 1.61 0.03 ◯ ◯ 1.64 0.03 ⊚ ◯ 1.63 0.02 ◯ ◯ 1.62 0.10 Δ ◯1.62 0.03 ◯ ◯ 1.61 0.10 Δ ◯

TABLE 2-2 SAMPLE CONDITION LASER WELDING SERRATION AREA RATIO OF VICKERSHARDNESS CONDITION (NUMBER OF ANNEALED PORTION IN Hv HOW TO LASER SWEEPSERRATIONS) CROSS-SECTIONAL TERMINAL BASE SET PRIOR POWER RATE CRIMPREAR END OBSERVATION BASE ANNEALED MATERIAL TO WELDING (W) (mm/sec)PORTION PORTION % MATERIAL PORTION EXAM- C2600 BUTTED 150 150 0 1 40 150127 PLE 250 45 150 125 350 50 147 126 150 200 25 145 129 250 25 147 123350 30 150 123 150 250 10 150 124 250 10 146 125 350 15 146 130 150 1501 1 40 149 125 250 45 149 123 350 50 146 125 150 200 25 149 129 250 25150 131 350 30 148 131 150 250 10 148 132 250 10 147 127 350 15 148 129EVALUATION RESULT SPRING-BACK ANTICORROSION EVALUATION PROPERTYDIFFERENCE EVALUATION BETWEEN As AND WORKABILITY AMOUNT OF RESISTANCERESISTANCE EVALUATION CORROSION AFTER mΩ AFTER BEING CRACKINGENVIRONMENTAL As LET STAND AFTER CRIMPING TEST EXAM- 1.70 0.11 Δ ⊚ PLE1.74 0.03 ◯ ⊚ 1.73 0.18 Δ ⊚ 1.73 0.01 ◯ ⊚ 1.74 0.01 ⊚ ⊚ 1.74 0.02 ◯ ⊚1.73 0.12 Δ ⊚ 1.71 0.03 ◯ ⊚ 1.71 0.11 Δ ⊚ 1.63 0.17 Δ ⊚ 1.62 0.01 ◯ ⊚1.64 0.11 Δ ⊚ 1.63 0.02 ◯ ⊚ 1.60 0.03 ⊚ ⊚ 1.61 0.03 ◯ ⊚ 1.62 0.13 Δ ⊚1.60 0.02 ◯ ⊚ 1.60 0.11 Δ ⊚

TABLE 2-3 SAMPLE CONDITION LASER WELDING SERRATION AREA RATIO OF VICKERSHARDNESS CONDITION (NUMBER OF ANNEALED PORTION IN Hv HOW TO LASER SWEEPSERRATIONS) CROSS-SECTIONAL TERMINAL BASE SET PRIOR POWER RATE CRIMPREAR END OBSERVATION BASE ANNEALED MATERIAL TO WELDING (W) (mm/sec)PORTION PORTION % MATERIAL PORTION EXAM- C2600 BUTTED 150 150 2 2 40 150127 PLE 250 45 149 125 350 50 146 124 150 200 25 147 132 250 25 145 126350 30 150 128 150 250 10 145 127 250 10 145 127 350 15 149 125 LAPPED200 200 0 0 25 145 130 1 1 25 150 127 ANGLED 200 200 0 0 25 150 131 1 125 149 132 COM- F CRIMP — 145 — PAR- BUTTED 100 100 0 0 70 147 138 ATIVE400 300 0 0  5 146 101 EXAM- PLE EVALUATION RESULT SPRING-BACKANTICORROSION EVALUATION PROPERTY DIFFERENCE EVALUATION BETWEEN As ANDWORKABILITY AMOUNT OF RESISTANCE RESISTANCE EVALUATION CORROSION AFTERmΩ AFTER BEING CRACKING ENVIRONMENTAL As LET STAND AFTER CRIMPING TESTEXAM- 1.61 0.12 Δ ⊚ PLE 1.60 0.02 ◯ ⊚ 1.60 0.19 Δ ⊚ 1.62 0.01 ◯ ⊚ 1.600.01 ⊚ ⊚ 1.62 0.01 ◯ ⊚ 1.64 0.10 Δ ⊚ 1.61 0.01 ◯ ⊚ 1.60 0.10 Δ ⊚ 1.740.01 ⊚ Δ 1.72 0.02 ⊚ ◯ 1.74 0.03 ⊚ Δ 1.74 0.02 ⊚ ◯ COM- 1.73 0.01 ⊚ XPAR- 1.72 0.34 X ◯ ATIVE 1.72 0.26 X X EXAM- PLE

A third example will be described below. In the first example, analuminum alloy MSA1 (strip, thickness 0.25 mm) manufactured by FurukawaElectric Co., Ltd. was used as the base material of the terminal. MSA1is an alloy having a composition of approximately 0.2% iron (Fe),approximately 0.2% copper (Cu), approximately 0.1% magnesium (Mg),approximately 0.04% silicon (Si), and the balance containing aluminum(Al) and incidental impurities. Note that at least a part of the metalbase material in which the weld portion was formed was constituted usinga metal member on which a tin plating was applied as a plating portion.Other than the above, a terminal having a shape similar to that of thefirst example was constituted and an evaluation similar to that of thefirst example was performed and evaluation results thereof are shown inTables 3-1 to 3-3.

TABLE 3-1 SAMPLE CONDITION LASER WELDING SERRATION AREA RATIO OF VICKERSHARDNESS CONDITION (NUMBER OF ANNEALED PORTION IN Hv HOW TO LASER SWEEPSERRATIONS) CROSS-SECTIONAL TERMINAL BASE SET PRIOR POWER RATE CRIMPREAR END OBSERVATION BASE ANNEALED MATERIAL TO WELDING (W) (mm/sec)PORTION PORTION % MATERIAL PORTION EXAM- MSAI BUTTED 200 100 0 0 35 8062 PLE 300 40 89 63 400 40 83 64 200 150 20 87 65 300 20 81 64 400 25 8360 200 200 10 84 60 300 10 87 65 400 10 83 60 200 100 1 0 35 80 69 30040 89 64 400 40 86 61 200 150 20 87 65 300 20 88 64 400 25 83 64 200 20010 80 67 300 10 80 65 400 10 87 62 EVALUATION RESULT SPRING-BACKANTICORROSION EVALUATION PROPERTY DIFFERENCE EVALUATION BETWEEN As ANDWORKABILITY AMOUNT OF RESISTANCE RESISTANCE EVALUATION CORROSION AFTERmΩ AFTER BEING CRACKING ENVIRONMENTAL As LET STAND AFTER CRIMPING TESTEXAM- 1.81 0.10 Δ ◯ PLE 1.83 0.01 ◯ ◯ 1.82 0.13 Δ ◯ 1.82 0.01 ◯ ◯ 1.800.02 ⊚ ◯ 1.84 0.01 ◯ ◯ 1.84 0.14 Δ ◯ 1.83 0.01 ◯ ◯ 1.80 0.11 Δ ◯ 1.740.15 Δ ◯ 1.73 0.01 ◯ ◯ 1.74 0.17 Δ ◯ 1.70 0.01 ◯ ◯ 1.73 0.01 ⊚ ◯ 1.710.01 ◯ ◯ 1.70 0.19 Δ ◯ 1.71 0.02 ◯ ◯ 1.74 0.10 Δ ◯

TABLE 3-2 SAMPLE CONDITION LASER WELDING SERRATION AREA RATIO OF VICKERSHARDNESS CONDITION (NUMBER OF ANNEALED PORTION IN Hv HOW TO LASER SWEEPSERRATIONS) CROSS-SECTIONAL TERMINAL BASE SET PRIOR POWER RATE CRIMPREAR END OBSERVATION BASE ANNEALED MATERIAL TO WELDING (W) (mm/sec)PORTION PORTION % MATERIAL PORTION EXAM- MSAI BUTTED 200 100 0 1 35 8066 PLE 300 40 89 67 400 40 89 67 200 150 20 84 61 300 20 86 68 400 25 8363 200 200 10 81 64 300 10 85 68 400 10 86 63 200 100 1 1 35 83 60 30040 82 63 400 40 87 68 200 150 20 85 63 300 20 89 65 400 20 86 62 200 20010 81 64 300 10 88 64 400 10 80 61 EVALUATION RESULT SPRING-BACKANTICORROSION EVALUATION PROPERTY DIFFERENCE EVALUATION BETWEEN As ANDWORKABILITY AMOUNT OF RESISTANCE RESISTANCE EVALUATION CORROSION AFTERmΩ AFTER BEING CRACKING ENVIRONMENTAL As LET STAND AFTER CRIMPING TESTEXAM- 1.81 0.14 Δ ⊚ PLE 1.80 0.03 ◯ ⊚ 1.82 0.19 Δ ⊚ 1.81 0.01 ◯ ⊚ 1.830.02 ⊚ ⊚ 1.84 0.01 ◯ ⊚ 1.82 0.15 Δ ⊚ 1.81 0.03 ◯ ⊚ 1.82 0.12 Δ ⊚ 1.720.16 Δ ⊚ 1.71 0.03 ◯ ⊚ 1.72 0.14 Δ ⊚ 1.74 0.01 ◯ ⊚ 1.73 0.03 ⊚ ⊚ 1.730.01 ◯ ⊚ 1.73 0.12 Δ ⊚ 1.74 0.02 ◯ ⊚ 1.74 0.15 Δ ⊚

TABLE 3-3 SAMPLE CONDITION LASER WELDING SERRATION AREA RATIO OF VICKERSHARDNESS CONDITION (NUMBER OF ANNEALED PORTION IN Hv HOW TO LASER SWEEPSERRATIONS) CROSS-SECTIONAL TERMINAL BASE SET PRIOR POWER RATE CRIMPREAR END OBSERVATION BASE ANNEALED MATERIAL TO WELDING (W) (mm/sec)PORTION PORTION % MATERIAL PORTION EXAM- MSAI BUTTED 200 100 2 2 35 8769 PLE 300 40 83 69 400 40 88 66 200 150 20 85 62 300 20 84 63 400 20 8466 200 200 10 84 60 300 10 88 65 400 10 85 63 LAPPED 300 150 0 0 20 8466 1 1 20 87 63 ANGLED 300 150 0 0 20 82 68 1 1 20 86 61 COM- F CRIMP —86 — PAR- BUTTED 100  50 0 0 65 86 78 ATIVE 500 250 0 0  5 86 60 EXAM-PLE EVALUATION RESULT SPRING-BACK ANTICORROSION EVALUATION PROPERTYDIFFERENCE EVALUATION BETWEEN As AND WORKABILITY AMOUNT OF RESISTANCERESISTANCE EVALUATION CORROSION AFTER mΩ AFTER BEING CRACKINGENVIRONENTAL As LET STAND AFTER CRIMPING TEST EXAM- 1.71 0.18 Δ ⊚ PLE1.74 0.02 ◯ ⊚ 1.74 0.18 Δ ⊚ 1.74 0.03 ◯ ⊚ 1.73 0.03 ⊚ ⊚ 1.73 0.03 ◯ ⊚1.71 0.12 Δ ⊚ 1.73 0.03 ◯ ⊚ 1.71 0.12 Δ ⊚ 1.70 0.01 ⊚ Δ 1.74 0.01 ⊚ ◯1.73 0.01 ⊚ Δ 1.71 0.03 ⊚ ◯ COM- 1.71 0.01 ⊚ X PAR- 1.72 0.36 X ◯ ATIVE1.72 0.24 X X EXAM- PLE

As can be seen from Tables 1-1 to 1-3, when the annealed portion havinga hardness (Vickers hardness) of 72 to 84% of the hardness of the copperalloy base material has 10 to 60% of an area ratio with respect to thetubular crimp portion, cracking after crimping, which is workabilityevaluation, showed evaluations indicated by symbol ⊚, symbol ◯, andsymbol Δ. Also for lapped welding and angled welding, the cracking aftercrimping, which is workability evaluation, showed evaluations indicatedby symbol ◯, and good results were obtained. Further, the amount ofcorrosion after the environmental test as an anticorrosion evaluationhad a good corrosion performance which showed that, in the case of buttwelding, the aluminum core wire remained without corrosion (symbol ⊚)or, some corrosion (spot-like corrosion and pitting corrosion) wasobserved in an outer periphery of the aluminum core wire (symbol ◯).Also for lapped welding and angled welding, some corrosion (spot-likecorrosion and pitting corrosion) was observed in an outer periphery ofthe aluminum core wire (symbol ◯) or 50% or more area ratio of thealuminum core wire remained (symbol Δ).

Also, as can be seen from Tables 2-1 to 2-3, when the annealed portionhaving a hardness (Vickers hardness) of 82 to 90% of the hardness of thecopper alloy base material has 5 to 50% of an area ratio with respect tothe tubular crimp portion, the cracking after crimping, which isworkability evaluation, showed evaluations indicated by symbol ⊚, symbol◯, and symbol Δ. Also for lapped welding and angled welding, thecracking after crimping, which is workability evaluation, showedevaluations indicated by symbol ◯, and good results were obtained.Further, the amount of corrosion after the environmental test as ananticorrosion evaluation had a good corrosion performance which showedthat, in the case of butt welding, the aluminum core wire remainedwithout corrosion (symbol ⊚), or, some corrosion (spot-like corrosionand pitting corrosion) was observed in an outer periphery of thealuminum core wire (symbol ◯). Also for lapped welding and angledwelding, some corrosion (spot-like corrosion and pitting corrosion) wasobserved in an outer periphery of the aluminum core wire (symbol ◯) or50% or more area ratio of the aluminum core wire remained (symbol Δ).

On the other hand, in a comparative example in which the tubular crimpportion does not have an annealed portion, the cracking after crimpingshowed evaluation indicated by symbol ◯, but the amount of corrosionafter the environmental test showed an evaluation that 50% or more arearatio of aluminum has disappeared (symbol x).

Further, as can be seen from Tables 3-1 to 3-3, when the annealedportion having a hardness (Vickers hardness) of 70 to 87% of thehardness of the aluminum alloy base material has 5 to 40% of an arearatio with respect to the tubular crimp portion, the cracking aftercrimping, which is workability evaluation, showed evaluations indicatedby symbol ⊚, symbol ◯, and symbol Δ. Also for lapped welding and angledwelding, the cracking after crimping, which is workability evaluation,showed evaluations indicated by symbol ⊚, and good results wereobtained. Further, the amount of corrosion after the environmental testas an anticorrosion evaluation had a good corrosion performance whichshowed that, in the case of butt welding, the aluminum core wireremained without corrosion (symbol ⊚), or, some corrosion (spot-likecorrosion and pitting corrosion) was observed in an outer periphery ofthe aluminum core wire (symbol ◯). Also for lapped welding and angledwelding, some corrosion (spot-like corrosion and pitting corrosion) wasobserved in an outer periphery of the aluminum core wire (symbol ◯) or50% or more area ratio of the aluminum core wire remained (symbol Δ).

Thus, it was found that, with the terminal having the annealed portionthat was softer than the hardness of the metal base material in thetubular crimp portion, the cracking after crimping can be reduced andspringback can be prevented by suppressing an amount of corrosion afterthe environmental test. Also, it was found that, when viewed in a crosssection perpendicular to the longitudinal direction of a tubular crimpportion, if the annealed portion having a hardness of 70 to 90% of thehardness of the base material constituting the terminal has an arearatio of 5 to 60% of the tubular crimp portion, the cracking aftercrimping can be reduced and springback can be prevented by suppressingan amount of corrosion after the environmental test.

Next, a fourth example will be described. In the fourth example, acopper alloy FAS-680 (thickness 0.25 mm) manufactured by FurukawaElectric Co., Ltd. was used as the base material of the terminal 1.FAS-680 is an alloy having a composition containing 2.0 to 2.8 mass %nickel (Ni), 0.45 to 0.6 mass % silicon (Si), 0.4 to 0.55 mass % zinc(Zn), 0.1 to 0.25 mass % tin (Sn), 0.05 to 0.2 mass % magnesium (Mg),and the balance is copper (Cu) and incidental impurities. At least at apart of the metal base material in which the weld portion was formed wasconstituted using a metal member on which a tin plating was applied wasused as a plating portion.

The core wire of the aluminum wire was a wire having a wire size of 0.43mm. The composition of the alloy of the core wire contains approximately0.2% iron (Fe), approximately 0.2% copper (Cu), approximately 0.1%magnesium (Mg), approximately 0.04% silicon (Si), and the balance isaluminum (Al) and incidental impurities. A 2.5 sq (mm²), 19 strandtwisted wire was made using this core wire.

The tubular crimp portion 30 of the terminal 1 was formed by laserwelding the crimp portion as described above. As for the tubular crimpportion 30 formed in such a manner, an area ratio of the weld portion 70with respect to the non-weld portion 100 (the normal portion 90 and theannealed portion 80 as well as a plating portion optionally provided onsurfaces thereof) in a cross section perpendicular to the longitudinaldirection of the tubular crimp portion 30 was observed. As has beendescribed above, for the calculation of the area ratio, the tubularcrimp portion was cut perpendicularly to the longitudinal direction andits cross section was observed with an SEM (Scanning ElectronMicroscope) and the weld portion 70 and the non-weld portion 100 (thenormal portion 90 and the annealed portion 80, and a plating portionoptionally provided on the surface of the metal base material thereof)were identified. Note that, as a measured value of the area ratio,measurements were performed ten times for the samples made under thesame condition and an average value thereof was rounded off to onedecimal place. For numerical values obtained in this manner, an errorrange of measurement was taken as +−0.2%, and indicated by taking 0.5%as a unit. For example, when the measurement value of the area ratio isin the range of 2.8 to 3.2, it was evaluated as 3.0.

The evaluation of the workability was performed using crack appearanceafter crimping. Specifically, the evaluation was performed by observingthe surface and the cross section of the tubular crimp portion with anelectron microscope such as an SEM (Scanning Electron Microscope) andcategorized using symbol ⊚ which denotes that no creases or the likewere observed, symbol ◯ which denotes that creases are observed but nocracks were produced, symbol Δ which denotes that cracks were producedbut only superficially, and symbol x which denotes that crackspenetrating through the base material were produced.

Experiment conditions are as follows:

-   -   Laser source used: 500 W CW fiber laser ASF1J233 (wavelength        1,084 nm single-mode oscillation laser light) manufactured by        Furukawa Electric Co., Ltd.    -   Laser light power: 300, 400, 500 W    -   Sweep rate: 90, 135, 180 mm/sec.    -   Sweep distance: 9 mm    -   Laser light irradiation with all conditions focused (spot size:        0.02 mm)

The aforementioned various test results and evaluation results are shownin Table 4.

TABLE 4 EVALUATION RESULT SAMPLE CONDITION AREA RATIO OF WELDWORKABILITY LASER WELDING CONDITION PORTION IN CROSS- EVALUATION BASELASER SWEEP RATE SECTIONAL OBSERVATION CRACKING AFTER MATERIAL POWER (W)(mm/sec) % CRIMPING EXAMPLE FAS-680 300 90 3.0 Δ 400 3.5 ◯ 500 5.0 Δ 300135 2.5 ◯ 400 3.0 ⊚ 500 3.5 ◯ 300 180 2.0 Δ 400 2.5 ◯ 500 3.0 ΔCOMPARATIVE FAS-680 300 200 1.0 X EXAMPLE 500 80 6.0 X

As can be seen from Table 4, when the tubular crimp portion was observedin a cross section perpendicular to the longitudinal direction thereof,in a case where the area ratio of the weld portion 70 with respect tothe non-weld portion 100 is 2 to 5%, the cracking after crimping, whichwas used in workability evaluation, showed evaluations indicated bysymbol ⊚, symbol ◯, and symbol Δ. Note that, as has been describedabove, the workability evaluation was performed by carrying out a crosssectional observation of the cracking after cramping and categorizedusing symbol ⊚ which denotes that no creases or the like were observed,symbol ◯ which denotes that creases were observed but no cracks wereproduced, symbol Δ which denotes that cracks were produced but onlysuperficially, and symbol x which denotes that cracks penetratingthrough the base material were produced.

Referring to Table 4, the highest evaluation indicated by symbol ⊚ wasobtained in a case where the laser power was 400 (W) and the sweep ratewas 135 (mm/sec). The second highest evaluation indicated by the symbol◯ was obtained in a case where the laser power was 300 (W) and the sweeprate was 135 (mm/sec), a case where the laser power was 400 (W) and thesweep rate was 90 or 180 (mm/sec), and a case where the laser power was500 (W) and the sweep rate was 135 (mm/sec). The evaluation indicated bythe symbol Δ was obtained in a case where the laser power was 300 (W)and the sweep rate was 90 or 180 (mm/sec) and a case where the laserpower was 500 (W) and the sweep rate was 90 or 180 (mm/sec).

Considering the above in relation to the area ratio of the weld portion70 with respect to the non-weld portion 100 viewed in a cross sectionperpendicular to the longitudinal direction of the tubular crimp portion30, the following was obtained. In the case of the laser power of 400(W) and the sweep rate of 135 (mm/sec) for which the highest evaluationindicated by the symbol ⊚ was obtained, the area ratio was approximately3. In the cases of the laser power of 300 (W) and the sweep rate of 135(mm/sec), the laser power of 400 (W) and the sweep rate of 90 or 180(mm/sec), and the laser power of 500 (W) and the sweep rate of 135(mm/sec) for which the second highest evaluation of the symbol ◯ wereobtained, the area ratio was 2.5 or 3.5. Further, in the cases of thelaser power of 300 (W) and the sweep rate of 90 or 180 (mm/sec), and thelaser power 500 (W) of the sweep rate of 90 or 180 (mm/sec) for whichthe evaluation of the symbol Δ was obtained, the area ratio was 3.0, 2.0or 5.0

From the test results mentioned above, when laser welding is performedin such a manner that the region of the weld portion 70 has an arearatio of 2 to 5% with respect to the region of the non-weld portion 100(the normal portion 90 and annealed portion 80, and the plating portionoptionally provided on the surface of metal base material thereof) whenviewed in a cross section perpendicular to the longitudinal direction ofthe tubular crimp portion 30, the evaluation was “cracks were producedbut only superficially” or better, and it was seen that the crackingduring crimping of the tubular crimp portion 30 (cracks penetratingthrough the base material) can be prevented.

As described above, it was seen that the cracking during crimping in thetubular crimp portion 30 of the present disclosure can be prevented bysetting the area ratio of the weld portion 70 with respect to the regionof the non-weld portion 100 (the normal portion 90 and annealed portion80, and the plating portion optionally provided on the surface of themetal base material thereof) as described above, when forming thetubular crimp portion 30 by laser welding. In the present disclosure, apreferable ratio of the area ratio between the weld portion and thenon-weld portion was found under the contradicting requirements of“workability” and “strength”, while considering the property of the weldportion which is easy to be bent but has a reduced strength due toannealing and the property of the non-weld portion which is moredifficult to be bent but has an increased strength as compared to theweld portion. As has been described above, the fourth example can beimplemented in addition to or separately from the first example.

Next, a fifth example will be described. In the fifth example, the basematerial of the terminal 1 was an aluminum alloy MSA1 (strip, thickness0.25 mm) manufactured by Furukawa Electric Co., Ltd. MSA1 is an alloyhaving a composition containing approximately 0.2% iron (Fe),approximately 0.2% copper (Cu), approximately 0.1% magnesium (Mg),approximately 0.04% silicon (Si), and the balance is aluminum (Al) andincidental impurities. At least at a part of the metal base material inwhich the weld portion is formed was constituted using a metal member onwhich a tin plating was applied as a plating portion.

The core wire of the aluminum wire and the tubular crimp portion 30 ofthe terminal 1 are formed in a similar manner to the case for theaforementioned copper alloy. Also, the area ratio of the weld portion 70with respect to the region of the non-weld portion 100 (the normalportion 90 and annealed portion 80, and the plating portion optionallyprovided on the surface of the metal base material thereof) when viewedin a cross section perpendicular to the longitudinal direction of thetubular crimp portion 30 was identified in a manner similar to the caseof the copper alloy described above.

Similarly to the above, the evaluation of the workability was performedusing crack appearance after crimping. Evaluation was made by observingthe surface and the cross section of the tubular crimp portion with anelectron microscope such as the SEM (Scanning Electron Microscope), andcategorizing using symbol ⊚ which denotes that no creases or the likewere observed, symbol ◯ which denotes that creases were observed but nocracks were produced, symbol Δ which denotes that cracks were producedbut only superficially, and symbol x which denotes that crackspenetrating through the base material were produced.

Experiment conditions are as follows:

-   -   Laser source used: 500 W CW fiber laser ASF1J233 (wavelength        1,084 nm single-mode oscillation laser light) manufactured by        Furukawa Electric Co., Ltd.    -   Laser light power: 200, 300, 400 W    -   Sweep rate: 100, 150, 200 mm/sec.    -   Sweep distance: 9 mm    -   Laser light irradiation with all conditions focused (spot size:        0.02 mm)

The aforementioned various test results and evaluation results are shownin Table 5.

TABLE 5 EVALUATION RESULT SAMPLE CONDITION AREA RATIO OF WELDWORKABILITY LASER WELDING CONDITION PORTION IN CROSS- EVALUATION BASELASER SWEEP RATE SECTIONAL OBSERVATION CRACKING AFTER MATERIAL POWER (W)(mm/sec) % CRIMPING EXAMPLE MSAL 200 100 3.0 Δ 300 3.5 ◯ 400 5.0 Δ 200150 2.5 ◯ 300 3.0 ⊚ 400 3.5 ◯ 200 200 2.0 Δ 300 2.5 ◯ 400 3.0 ΔCOMPARATIVE MSAL 200 200 1.0 X EXAMPLE 400 80 6.0 X

As can be seen from Table 5, when the tubular crimp portion was observedin a cross section perpendicular to the longitudinal direction thereof,in a case where the area ratio of the weld portion 70 with respect tothe non-weld portion 100 is 2 to 5%, the cracking after crimping whichwas used for workability evaluation was evaluated using symbol ⊚, symbol◯, and symbol Δ. Note that, as has been described above, the workabilityevaluation was performed by carrying out a cross sectional observationof the cracking after cramping and categorizing using symbol ⊚ whichdenotes that no creases were observed, symbol ◯ which denotes thatcreases were observed but no cracks were produced, symbol Δ whichdenotes that cracks were produced but only superficially, and symbol xwhich denotes that cracks penetrating through the base material wereproduced.

Referring to Table 5, the highest evaluation indicated by symbol ⊚ wasobtained in a case where the laser power was 300 (W) and the sweep ratewas 150 (mm/sec). The second highest evaluation indicated by symbol ◯was obtained in a case where the laser power was 200 (W) and the sweeprate was 150 (mm/sec), a case where the laser power was 300 (W) and thesweep rate was 100 or 200 (mm/sec), and a case where the laser power was400 (W) and the sweep rate was 150 (mm/sec). The evaluation indicated bysymbol Δ was obtained in a case where the laser power was 200 (W) andthe sweep rate was 100 or 200 (mm/sec) and a case where the laser powerwas 400 (W) and the sweep rate was 100 or 200 (mm/sec).

Considering the above in relation to the area ratio of the weld portion70 with respect to the non-weld portion 100 viewed in a cross sectionperpendicular to the longitudinal direction of the tubular crimp portion30, the following was obtained. In the case of the laser power of 300(W) and the sweep rate of 150 (mm/sec) for which the highest evaluationindicated by the symbol ⊚, the area ratio was approximately 3. In thecases of the laser power of 200 (W) and the sweep rate of 150 (mm/sec),the laser power of 300 (W) and the sweep rate of 100 or 200 (mm/sec),and the laser power of 400 (W) and the sweep rate of 150 (mm/sec) forwhich the second highest evaluation of the symbol ◯ was obtained, thearea ratio was 2.5 or 3.5. Further, in the cases of the laser power of200 (W) and the sweep rate of 100 or 200 (mm/sec), and the laser power400 (W) of the sweep rate of 100 or 200 (mm/sec) for which theevaluation of the symbol Δ was obtained, the area ratio was 3.0, 2.0 or5.0

From the test results mentioned above, similarly to the case of thecopper alloy, when laser welding is performed in such a manner that theregion of the weld portion 70 has an area ratio of 2 to 5% with respectto the region of the non-weld portion 100 (the normal portion 90 andannealed portion 80, and the plating portion optionally provided on thesurface of metal base material thereof) when viewed in a cross sectionperpendicular to the longitudinal direction of the tubular crimp portion30, the evaluation was “cracks were produced but only superficially” orbetter, and it was seen that the cracking during the crimping of thetubular crimp portion 30 (cracks penetrating through the base material)can be prevented.

Further, a sixth example will be described. In the sixth example, acopper alloy FAS-680 (thickness 0.25 mm) manufactured by FurukawaElectric Co., Ltd. was used as the metal base material of the terminal1. FAS-820 is an alloy having a composition containing approximately 2.3mass % nickel (Ni), approximately 0.65 mass % silicon (Si),approximately 0.5 mass % zinc (Zn), approximately 0.15 mass % tin (Sn),approximately 0.15 mass % chromium (Cr), and approximately 0.1 mass %magnesium (Mg), and the balance is copper (Cu) and incidentalimpurities. At least at a part of the metal base material in which theweld portion was constituted using a metal member on which a tin platingwas applied was used as a plating portion.

The core wire of the aluminum wire was a wire having a wire size of 0.3mm. The core wire is an alloy having a composition of approximately 0.2%iron (Fe), approximately 0.2% copper (Cu), approximately 0.1% magnesium(Mg), and approximately 0.04% silicon (Si), and the balance is aluminum(Al) and incidental impurities. This core wire was an electric wire of11 strand circular compression twisted wire of 0.75 sq (mm²).

The tubular crimp portion 30 of the terminal 1 was formed by laserwelding the crimp portion as described above. For the tubular crimpportion 30 formed in this manner, the hardness of each of the weldportion 70 and the normal portion 90 was measured in a cross sectionperpendicular to a predetermined longitudinal direction of the tubularcrimp portion 30, and thereafter, a ratio of the hardness of the normalportion 90 with respect to the hardness of the weld portion 70 wasobserved. The measurement of the hardness was performed by measuring theVickers hardness (Hv) by a Vickers test. Note that, the measurement ofthe Vickers hardness (Hv) of the weld portion was performed at thecenter position of the weld portion in a cross section perpendicular toa predetermined longitudinal direction of the tubular crimp portion 30,and measurement of the Vickers hardness (Hv) of the normal portion wasmeasured at a position approximately 180 degrees in a peripheraldirection from the center position of the weld portion of the normalportion in a cross section perpendicular to the predeterminedlongitudinal direction of the tubular crimp portion 30 (see FIG. 4).Note that, as a measured value of the Vickers hardness (Hv),measurements were performed ten times for the samples made under thesame condition and an average value thereof was rounded off to onedecimal place.

The evaluation of the workability was performed using crack appearanceafter crimping. Specifically, the evaluation was performed by observingthe surface and the cross section of the tubular crimp portion with anelectron microscope such as an SEM (Scanning Electron Microscope), andcategorized using symbol ⊚ which denotes that creases or the like wereobserved, symbol ◯ which denotes that creases were observed but nocracks were produced, symbol Δ which denotes that cracks were producedbut only superficially, and symbol x which denotes that crackspenetrating through the base material were produced.

Experiment conditions are as follows:

-   -   Laser source used: 500 W CW fiber laser ASF1J233 (wavelength        1,084 nm single-mode oscillation laser light) manufactured by        Furukawa Electric Co., Ltd.    -   Laser light power: 300, 400, 500 W    -   Sweep rate: 90, 135, 180 mm/sec.    -   Sweep distance: 9 mm    -   Laser light irradiation with all conditions focused (spot size:        0.02 mm)

The aforementioned various test results and evaluation results are shownin Table 6.

TABLE 6 SAMPLE CONDITION EVALUATION RESULT LASER WELDING CONDITIONVICKERS HARDNESS Hv BASE LASER POWER SWEEP RATE TERMINAL BASEWORKABILITY EVALUATION MATERIAL (W) (mm/sec) MATERIAL WELD PORTIONCRACKING AFTER CRIMPING EXAMPLE FAS-680 300 90 203 89 Δ 400 201 83 ◯ 500220 82 Δ 300 135 215 94 ◯ 400 210 89 ⊚ 500 220 88 ◯ 300 180 219 104 Δ400 205 93 ◯ 500 213 91 Δ COMPARATIVE FAS-680 300 200 210 106 X EXAMPLE500 80 217 77 X

Table 6 shows results of measurement of Vickers hardness (Hv) of thenormal portion 90 (terminal base material) and the weld portion 70 andobservation of cracking after crimping, under various conditions oflaser welding. The measurement of the Vickers hardness (Hv) wasperformed in conformity with JIS Z 2244. In a case where the Vickershardness (Hv) of the weld portion 70 and of the normal portion 90 are106 (Hv) and 210 (Hv), respectively, and, a case where they are 77 (Hv)and 217 (Hv), respectively, cracks that penetrate through the basematerial were produced, and, in cases other than the above, the crackingafter crimping was evaluated by the symbol ⊚, the symbol ◯ or the symbolΔ. Note that, as has been described above, the workability evaluationwas performed by carrying out a cross sectional observation of thecracking after cramping and categorizing using symbol ⊚ which denotesthat no creases or the like were observed, symbol ◯ which denotes thatcreases were observed but no cracks were produced, symbol Δ whichdenotes that cracks were produced but only superficially, and symbol xwhich denotes that cracks penetrating through the base material wasproduced.

Referring to Table 6, the highest evaluation indicated by the symbol ⊚was obtained in a case where the laser power was 400 (W) and the sweeprate was 135 (mm/sec). The second highest evaluation indicated by thesymbol ◯ was obtained in a case where the laser power was 300 (W) andthe sweep rate was 135 (mm/sec), a case where the laser power was 400(W) and the sweep rate was 90 or 180 (mm/sec), and a case where thelaser power was 500 (W) and the sweep rate was 135 (mm/sec). Theevaluation indicated by the symbol Δ was obtained in a case where thelaser power was 300 (W) and the sweep rate was 90 or 180 (mm/sec) and acase where the laser power was 500 (W) and the sweep rate was 90 or 180(mm/sec).

Considering the above in relation to the ratio of the Vickers hardness(Hv) of the normal portion 90 with respect to the Vickers hardness (Hv)of the weld portion 70 viewed in a cross section perpendicular to thepredetermined longitudinal direction of the tubular crimp portion 30,the following was obtained. In the case of the laser power of 400 (W)and the sweep rate of 135 (mm/sec) for which the highest evaluationindicated by the symbol ⊚ was obtained, the ratio of the Vickershardness (Hv) was 2.36. In the case where the laser power of 300 (W) andthe sweep rate of 135 (mm/sec), the case where the laser power of 400(W) and the sweep rate of 90 or 180 (mm/sec), and the laser power of 500(W) and the sweep rate of 135 (mm/sec) for which the second highestevaluation of the symbol ◯ was obtained, the ratio of the Vickershardness (Hv) was 2.29, 2.42, 2.20 or 2.50. Further, in the case wherethe laser power of 300 (W) and the sweep rate of 90 or 180 (mm/sec), andthe case where the laser power 500 (W) of the sweep rate of 90 or 180(mm/sec) for which the evaluation of the symbol Δ was obtained, theratio of the Vickers hardness (Hv) was 2.28, 2.11, 2.68 or 2.34.

From the test results mentioned above, when laser welding is performedin such a manner that the ratio of the hardness of the region of thenormal portion 90 with respect to the hardness of the region of the weldportion 70 is 2.1 to 2.7, the evaluation was “cracks were produced butonly superficially” or better, and it was seen that the cracking duringcrimping of the tubular crimp portion 30 (cracks penetrating through thebase material) can be prevented. Further, when the laser welding isperformed in such a manner that the ratio of the hardness of the regionof the normal portion 90 with respect to the hardness of the region ofthe weld portion 70 is 2.2 to 2.5, the evaluation was “no creases norcracks were observed” or “creases were observed but cracks per se werenot produced”, and it was seen that the cracking during crimping of thetubular crimp portion 30 (cracks penetrating through the base material)can be prevented and also cracks in the superficial layer during thecrimping of the tubular crimp portion 30 can be prevented. Further, whenthe laser welding is performed in such a manner that the ratio of thehardness of the region of the normal portion 90 with respect to thehardness of the region of the weld portion 70 is 2.3 to 2.4, a goodresult was obtained in which no cracks per se during the crimping of thetubular crimp portion 30 were produced and no creases or the like wereobserved.

As described above, when forming the tubular crimp portion 30 by laserwelding, by performing the welding in such a manner that the ratio ofthe hardness of the normal portion 90 of the non-weld portion 100 withrespect to the weld portion 70 is as described above, it was found thatthe terminal 1 having the tubular crimp portion 30 of the presentdisclosure is capable of preventing the cracking during crimping. Notethat, as has been described above, the sixth example can be implementedin addition to the first example or separately from the first example.

Next, a seventh example will be described. In the seventh example, analuminum alloy MSA1 (strip, thickness 0.25 mm) manufactured by FurukawaElectric Co., Ltd was used as the metal base material of the terminal 1.MSA1 is an alloy having a composition containing approximately 0.2% iron(Fe), approximately 0.2% copper (Cu), approximately 0.1% magnesium (Mg),approximately 0.04% silicon (Si), and the balance is aluminum (Al) andincidental impurities. At least at a part of the metal base material inwhich the weld portion was formed, a metal member on which a tin platingwas applied was used as a plating portion.

The formation of the core wire of the aluminum wire and the tubularcrimp portion 30 of the terminal 1 is similar to the case of theaforementioned copper alloy. Also, the area ratio of the weld portion 70with respect to the region of the non-weld portion 100 (the normalportion 90 and annealed portion 80, and the plating portion optionallyprovided on the surface of the metal base material thereof) when seen ina cross section perpendicular to the longitudinal direction of thetubular crimp portion 30 was identified in the similar manner to thecase for the copper alloy described above.

Similarly to the above, evaluation of the workability was performedusing crack appearance after crimping. Evaluation was made by observingthe surface and the cross section of the tubular crimp portion with anelectron microscope such as the SEM (Scanning Electron Microscope), andcategorizing using symbol ⊚ which denotes that no creases or the likewere observed, symbol ◯ which denotes that creases were observed but nocracks were produced, symbol Δ which denotes that cracks were producedbut only superficially, and symbol x which denotes that crackspenetrating through the base material.

Experiment conditions are as follows:

-   -   Laser source used: 500 W CW fiber laser ASF1J233 (wavelength        1,084 nm single-mode oscillation laser light) manufactured by        Furukawa Electric Co., Ltd.    -   Laser light power: 200, 300, 400 W    -   Sweep rate: 100, 150, 200 mm/sec.    -   Sweep distance: 9 mm    -   Laser light irradiation with all conditions focused (spot size:        0.02 mm)

The aforementioned various test results and evaluation results are shownin Table 7.

TABLE 7 SAMPLE CONDITION EVALUATION RESULT LASER WELDING CONDITIONVICKERS HARDNESS Hv BASE LASER POWER SWEEP RATE TERMINAL BASEWORKABILITY EVALUATION MATERIAL (W) (mm/sec) MATERIAL WELD PORTIONCRACKING AFTER CRIMPING EXAMPLE MSAI 200 100 82 36 Δ 300 81 33 ◯ 400 8833 Δ 200 150 85 38 ◯ 300 88 38 ⊚ 400 90 36 ◯ 200 200 83 39 Δ 300 88 40 ◯400 86 37 Δ COMPARATIVE MSAI 200 220 83 43 X EXAMPLE 400 80 81 28 X

Table 7 shows results of measurement of Vickers hardness (Hv) of thenormal portion 90 (terminal base material) and the weld portion 70 andobservation of cracking after crimping, under various conditions oflaser welding. The measurement of the Vickers hardness (Hv) wasperformed in conformity with JIS Z 2244. In a case where the Vickershardness (Hv) of the weld portion 70 and the normal portion 90 are 43(Hv) and 83 (Hv), respectively, and, a case where these are 28 (Hv) and81 (Hv), respectively, cracks that penetrate through the base materialwere produced, and, in cases other than the above, the cracking aftercrimping was evaluated by symbol ⊚, symbol ◯ or symbol Δ. Note that, ashas been described above, the workability evaluation was performed bycarrying out a cross sectional observation of the cracking aftercramping and categorizing using symbol ⊚ which denotes that no creasesor the like were observed, symbol ◯ which denotes that creases wereobserved but no cracks were produced, symbol Δ which denotes that crackswere produced but only superficially, and symbol x which denotes thatcracks penetrating through the base material were produced.

Referring to Table 7, the highest evaluation indicated by the symbol ⊚was obtained in a case where the laser power was 300 (W) and the sweeprate was 150 (mm/sec). The second highest evaluation indicated by thesymbol ◯ was obtained in a case where the laser power was 200 (W) andthe sweep rate was 150 (mm/sec), a case where the laser power was 300(W) and the sweep rate was 100 or 200 (mm/sec), and a case where thelaser power was 400 (W) and the sweep rate was 150 (mm/sec). Theevaluation indicated by the symbol Δ was obtained in a case where thelaser power was 200 (W) and the sweep rate was 100 or 200 (mm/sec) and acase where the laser power was 400 (W) and the sweep rate was 100 or 200(mm/sec).

Considering the above in relation to the ratio the Vickers hardness (Hv)of the normal portion 90 with respect to the Vickers hardness (Hv) ofthe weld portion 70 viewed in a cross section perpendicular to thepredetermined longitudinal direction of the tubular crimp portion 30,the following was obtained. In the case of the laser power of 300 (W)and the sweep rate of 150 (mm/sec) for which the highest evaluationindicated by the symbol ⊚ was obtained, the ratio of the Vickershardness (Hv) was 2.32. In the cases of the laser power of 200 (W) andthe sweep rate of 150 (mm/sec), the laser power of 300 (W) and the sweeprate of 100 or 200 (mm/sec), and the laser power of 400 (W) and thesweep rate of 150 (mm/sec) for which the second highest evaluation ofthe symbol ◯ was obtained, the ratio of the Vickers hardness (Hv) was2.24, 2.45, 2.20 or 2.50. Further, in the cases of the laser power of200 (W) and the sweep rate of 100 or 200 (mm/sec), and the laser power400 (W) of the sweep rate of 100 or 200 (mm/sec) which received theevaluation of the symbol Δ, the ratio of the Vickers hardness (Hv) was2.28, 2.13, 2.67 or 2.32.

From the test results mentioned above, similarly to the case of thecopper alloy, when laser welding is performed in such a manner that theratio of the hardness of the region of the normal portion 90 withrespect to the hardness of the region of the weld portion 70 is 2.1 to2.7, the evaluation was “cracks were produced but only superficially” orbetter, and it was seen that the cracking during crimping of the tubularcrimp portion 30 (cracks penetrating through the base material) can beprevented. Further, when the laser welding is performed in such a mannerthat the ratio of the hardness of the region of the normal portion 90with respect to the hardness of the region of the weld portion 70 is 2.2to 2.5, the evaluation was “no creases nor cracks were observed” or“creases were observed but no cracks per se were produced”, and it wasseen that the cracking during crimping of the tubular crimp portion 30(cracks penetrating through the base material) can be prevented and alsocracks in the superficial layer during the crimping of the tubular crimpportion 30 can be prevented. Further, when the laser welding isperformed in such a manner that the ratio of the hardness of the regionof the normal portion 90 with respect to the hardness of the region ofthe weld portion 70 is 2.3 to 2.4, a good result was obtained in whichcracks per se during the crimping of the tubular crimp portion 30 werenot produced and no creases or the like were observed.

As described above, when forming the tubular crimp portion 30 by laserwelding, by performing the welding in such a manner that the ratio ofthe hardness of the normal portion 90 of the non-weld portion 100 withrespect to the weld portion 70 is as described above, it was found thatthe terminal 1 having the tubular crimp portion 30 of the presentdisclosure is capable of preventing the cracking during crimping. Notethat, the seventh example can be implemented in addition to the thirdexample or separately from the third example.

What is claimed is:
 1. A terminal comprising a tubular crimp portionthat crimp connects with an electric wire, the tubular crimp portionbeing composed of a metal member, the tubular crimp portion including anon-weld portion and a weld portion, the weld portion being formed bylaser welding, wherein a metal base material constituting the metalmember of the non-weld portion includes an annealed portion, and an areaof the annealed portion located on a cross section perpendicular to alongitudinal direction of the tubular crimp portion, the area of theannealed portion being 5 to 60% of an area of the weld portion and thenon-weld portion.
 2. The terminal according to claim 1, wherein thenon-weld portion includes a non-annealed portion in addition to theannealed portion, and the annealed portion has a hardness of 70 to 90%of the non-annealed portion.
 3. The terminal according to claim 1,wherein, in a cross section perpendicular to a longitudinal direction ofthe tubular crimp portion, an area of the weld portion is 2 to 5% of anarea of the non-weld portion.
 4. The terminal according to claim 1,wherein the non-weld portion includes a non-annealed portion in additionto the annealed portion, and a ratio of a hardness of the non-annealedportion with respect to a hardness of the weld portion is 2.1 to 2.7. 5.The terminal according to claim 1, wherein the metal base material ismade of one of copper and a copper alloy.
 6. The terminal according toclaim 1, wherein the metal base material is made of one of aluminum andan aluminum alloy.
 7. A method of manufacturing a terminal having atubular crimp portion that crimp connects with an electric wire,comprising: forming a crimp portion having a C-shape in a cross sectionperpendicular to a longitudinal direction of the tubular crimp portionby bending a metal member; and forming the tubular crimp portion bylaser welding both ends of the crimp portion, wherein, by the welding, aweld portion is formed in the tubular crimp portion, and an annealedportion is formed in a non-weld portion, and in an area of the annealedportion located on a cross section perpendicular to a longitudinaldirection of the tubular crimp portion, the area of the annealed portionbeing 5 to 60% of an area of the weld portion and the non-weld portion.8. The method of manufacturing a terminal according to claim 7, whereinthe non-weld portion includes a non-annealed portion in addition to theannealed portion, and the annealed portion has a hardness of 70 to 90%of a hardness of the non-annealed portion.
 9. The method ofmanufacturing a terminal according to claim 7, wherein a tubular crimpportion is formed by welding such that, in a cross section perpendicularto a longitudinal direction of the tubular crimp portion, an area of theweld portion is 2 to 5% of an area of the non-weld portion.
 10. Themethod of manufacturing a terminal according to claim 7, whereinnon-weld portion includes a non-annealed portion in addition to theannealed portion, and the tubular crimp portion is formed by weldingsuch that, a ratio of the hardness of the non-annealed portion withrespect to the hardness of the weld portion is 2.1 to 2.7.
 11. Themethod of manufacturing a terminal according to claim 7, wherein a metalbase material constituting the metal member is made of one of copper anda copper alloy.
 12. The method of manufacturing a terminal according toclaim 7, wherein a metal base material constituting the metal member ismade of one of aluminum and an aluminum alloy.
 13. A terminationconnection structure of an electric wire comprising a configuration inwhich a terminal and an electric wire are crimp connected at the tubularcrimp portion of the terminal, the terminal including a tubular crimpportion that crimp connects with an electric wire, the tubular crimpportion being composed of a metal member, the tubular crimp portionincluding a non-weld portion and a weld portion, the weld portion beingformed by laser welding, wherein a metal base material constituting themetal member of the non-weld portion includes an annealed portion, andin an area of the annealed portion located on a cross sectionperpendicular to a longitudinal direction of the tubular crimp portion,the area of the annealed portion being 5 to 60% of an area of the weldportion and the non-weld portion.
 14. The termination connectionstructure of an electric wire according to claim 13, wherein theelectric wire is made of one of aluminum and an aluminum alloy.